problems.json

[
	{
	  "topic": "&#9939 Linked Lists",
	  "subtopics": [
		{
		  "title": "In-place traversal",
		  "problems": [
			{
			  "title": "Odd Even Linked List",
			  "url": "https://leetcode.com/problems/odd-even-linked-list",
			  "difficulty": "Medium"
			},
			{
			  "title": "Reverse Linked List",
			  "url": "https://leetcode.com/problems/reverse-linked-list",
			  "difficulty": "Easy"
			},
			{
			  "title": "Reverse Linked List II",
			  "url": "https://leetcode.com/problems/reverse-linked-list-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Reverse Nodes in k-Group",
			  "url": "https://leetcode.com/problems/reverse-nodes-in-k-group",
			  "difficulty": "Hard"
			},
			{
			  "title": "Rotate List",
			  "url": "https://leetcode.com/problems/rotate-list",
			  "difficulty": "Medium"
			},
			{
			  "title": "Swap Nodes in Pairs",
			  "url": "https://leetcode.com/problems/swap-nodes-in-pairs",
			  "difficulty": "Medium"
			}
		  ]
		},
		{
		  "title": "Fast & Slow pointers",
		  "problems": [
			{
			  "title": "Add Two Numbers",
			  "url": "https://leetcode.com/problems/add-two-numbers",
			  "difficulty": "Medium"
			},
			{
			  "title": "Linked List Cycle",
			  "url": "https://leetcode.com/problems/linked-list-cycle",
			  "difficulty": "Easy"
			},
			{
			  "title": "Linked List Cycle II",
			  "url": "https://leetcode.com/problems/linked-list-cycle-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Middle of the Linked List",
			  "url": "https://leetcode.com/problems/middle-of-the-linked-list",
			  "difficulty": "Easy"
			},
			{
			  "title": "Palindrome Linked List",
			  "url": "https://leetcode.com/problems/palindrome-linked-list",
			  "difficulty": "Easy"
			},
			{
			  "title": "Remove Duplicates from Sorted List",
			  "url": "https://leetcode.com/problems/remove-duplicates-from-sorted-list",
			  "difficulty": "Easy"
			},
			{
			  "title": "Remove Linked List Elements",
			  "url": "https://leetcode.com/problems/remove-linked-list-elements",
			  "difficulty": "Easy"
			},
			{
			  "title": "Remove Nth Node From End of List",
			  "url": "https://leetcode.com/problems/remove-nth-node-from-end-of-list",
			  "difficulty": "Medium"
			},
			{
			  "title": "Reorder List",
			  "url": "https://leetcode.com/problems/reorder-list",
			  "difficulty": "Medium"
			},
			{
			  "title": "Sort List",
			  "url": "https://leetcode.com/problems/sort-list",
			  "difficulty": "Medium"
			}
		  ]
		}
	  ]
	},
	{
	  "topic": "&#129526 Strings, Arrays, Stacks/Queues",
	  "subtopics": [
		{
		  "title": "Arrays",
		  "problems": [
			{
			  "title": "Circular Array Loop",
			  "url": "https://leetcode.com/problems/circular-array-loop",
			  "difficulty": "Medium"
			},
			{
			  "title": "Contains Duplicate",
			  "url": "https://leetcode.com/problems/contains-duplicate",
			  "difficulty": "Easy"
			},
			{
			  "title": "Find All Duplicates in an Array",
			  "url": "https://leetcode.com/problems/find-all-duplicates-in-an-array",
			  "difficulty": "Medium"
			},
			{
			  "title": "Find All Numbers Disappeared in an Array",
			  "url": "https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array",
			  "difficulty": "Easy"
			},
			{
			  "title": "Find the Duplicate Number",
			  "url": "https://leetcode.com/problems/find-the-duplicate-number",
			  "difficulty": "Medium"
			},
			{
			  "title": "First Missing Positive",
			  "url": "https://leetcode.com/problems/first-missing-positive",
			  "difficulty": "Hard"
			},
			{
			  "title": "Longest Consecutive Sequence",
			  "url": "https://leetcode.com/problems/longest-consecutive-sequence",
			  "difficulty": "Medium"
			},
			{
			  "title": "Missing Number",
			  "url": "https://leetcode.com/problems/missing-number",
			  "difficulty": "Easy"
			},
			{
			  "title": "Number of Matching Subsequences",
			  "url": "https://leetcode.com/problems/number-of-matching-subsequences",
			  "difficulty": "Medium"
			},
			{
			  "title": "Product of Array Except Self",
			  "url": "https://leetcode.com/problems/product-of-array-except-self",
			  "difficulty": "Medium"
			},
			{
			  "title": "Rotate Image",
			  "url": "https://leetcode.com/problems/rotate-image",
			  "difficulty": "Medium"
			},
			{
			  "title": "Set Matrix Zeroes",
			  "url": "https://leetcode.com/problems/set-matrix-zeroes",
			  "difficulty": "Medium"
			},
			{
			  "title": "Shortest Unsorted Continuous Subarray",
			  "url": "https://leetcode.com/problems/shortest-unsorted-continuous-subarray",
			  "difficulty": "Medium"
			},
			{
			  "title": "Single Number",
			  "url": "https://leetcode.com/problems/single-number",
			  "difficulty": "Easy"
			},
			{
			  "title": "Spiral Matrix",
			  "url": "https://leetcode.com/problems/spiral-matrix",
			  "difficulty": "Medium"
			},
			{
			  "title": "Word Search",
			  "url": "https://leetcode.com/problems/word-search",
			  "difficulty": "Medium"
			}
		  ]
		},
		{
		  "title": "Modified Binary Search",
		  "problems": [
			{
			  "title": "Binary Search",
			  "url": "https://leetcode.com/problems/binary-search",
			  "difficulty": "Easy"
			},
			{
			  "title": "Count of Range Sum",
			  "url": "https://leetcode.com/problems/count-of-range-sum",
			  "difficulty": "Hard"
			},
			{
			  "title": "Find Minimum in Rotated Sorted Array",
			  "url": "https://leetcode.com/problems/find-minimum-in-rotated-sorted-array",
			  "difficulty": "Medium"
			},
			{
			  "title": "Find Peak Element",
			  "url": "https://leetcode.com/problems/find-peak-element",
			  "difficulty": "Medium"
			},
			{
			  "title": "Find Smallest Letter Greater Than Target",
			  "url": "https://leetcode.com/problems/find-smallest-letter-greater-than-target",
			  "difficulty": "Easy"
			},
			{
			  "title": "Peak Index in a Mountain Array",
			  "url": "https://leetcode.com/problems/peak-index-in-a-mountain-array",
			  "difficulty": "Easy"
			},
			{
			  "title": "Search a 2D Matrix",
			  "url": "https://leetcode.com/problems/search-a-2d-matrix",
			  "difficulty": "Medium"
			},
			{
			  "title": "Search in Rotated Sorted Array",
			  "url": "https://leetcode.com/problems/search-in-rotated-sorted-array",
			  "difficulty": "Medium"
			},
			{
			  "title": "Search in Rotated Sorted Array II",
			  "url": "https://leetcode.com/problems/search-in-rotated-sorted-array-ii",
			  "difficulty": "Medium"
			}
		  ]
		},
		{
		  "title": "Sliding window",
		  "problems": [
			{
			  "title": "Count Unique Characters of All Substrings of a Given String",
			  "url": "https://leetcode.com/problems/count-unique-characters-of-all-substrings-of-a-given-string",
			  "difficulty": "Hard"
			},
			{
			  "title": "Fruit Into Baskets",
			  "url": "https://leetcode.com/problems/fruit-into-baskets",
			  "difficulty": "Medium"
			},
			{
			  "title": "Longest Repeating Character Replacement",
			  "url": "https://leetcode.com/problems/longest-repeating-character-replacement",
			  "difficulty": "Medium"
			},
			{
			  "title": "Longest Substring Without Repeating Characters",
			  "url": "https://leetcode.com/problems/longest-substring-without-repeating-characters",
			  "difficulty": "Medium"
			},
			{
			  "title": "Minimum Number of K Consecutive Bit Flips",
			  "url": "https://leetcode.com/problems/minimum-number-of-k-consecutive-bit-flips",
			  "difficulty": "Hard"
			},
			{
			  "title": "Minimum Size Subarray Sum",
			  "url": "https://leetcode.com/problems/minimum-size-subarray-sum",
			  "difficulty": "Medium"
			},
			{
			  "title": "Minimum Window Substring",
			  "url": "https://leetcode.com/problems/minimum-window-substring",
			  "difficulty": "Hard"
			},
			{
			  "title": "Permutation in String",
			  "url": "https://leetcode.com/problems/permutation-in-string",
			  "difficulty": "Medium"
			},
			{
			  "title": "Sliding Window Maximum",
			  "url": "https://leetcode.com/problems/sliding-window-maximum",
			  "difficulty": "Hard"
			},
			{
			  "title": "Substring with Concatenation of All Words",
			  "url": "https://leetcode.com/problems/substring-with-concatenation-of-all-words",
			  "difficulty": "Hard"
			}
		  ]
		},
		{
		  "title": "Two Pointers",
		  "problems": [
			{
			  "title": "3Sum",
			  "url": "https://leetcode.com/problems/3sum",
			  "difficulty": "Medium"
			},
			{
			  "title": "3Sum Closest",
			  "url": "https://leetcode.com/problems/3sum-closest",
			  "difficulty": "Medium"
			},
			{
			  "title": "Backspace String Compare",
			  "url": "https://leetcode.com/problems/backspace-string-compare",
			  "difficulty": "Easy"
			},
			{
			  "title": "Container With Most Water",
			  "url": "https://leetcode.com/problems/container-with-most-water",
			  "difficulty": "Medium"
			},
			{
			  "title": "Minimum Window Substring",
			  "url": "https://leetcode.com/problems/minimum-window-substring",
			  "difficulty": "Hard"
			},
			{
			  "title": "Remove Duplicates from Sorted List",
			  "url": "https://leetcode.com/problems/remove-duplicates-from-sorted-list",
			  "difficulty": "Easy"
			},
			{
			  "title": "Sort Colors",
			  "url": "https://leetcode.com/problems/sort-colors",
			  "difficulty": "Medium"
			},
			{
			  "title": "Squares of a Sorted Array",
			  "url": "https://leetcode.com/problems/squares-of-a-sorted-array",
			  "difficulty": "Easy"
			},
			{
			  "title": "Subarray Product Less Than K",
			  "url": "https://leetcode.com/problems/subarray-product-less-than-k",
			  "difficulty": "Medium"
			},
			{
			  "title": "Trapping Rain Water",
			  "url": "https://leetcode.com/problems/trapping-rain-water",
			  "difficulty": "Hard"
			},
			{
			  "title": "Two Sum",
			  "url": "https://leetcode.com/problems/two-sum",
			  "difficulty": "Easy"
			}
		  ]
		},
		{
		  "title": "Merge Intervals",
		  "problems": [
			{
			  "title": "Insert Interval",
			  "url": "https://leetcode.com/problems/insert-interval",
			  "difficulty": "Medium"
			},
			{
			  "title": "Interval List Intersections",
			  "url": "https://leetcode.com/problems/interval-list-intersections",
			  "difficulty": "Medium"
			},
			{
			  "title": "Merge Intervals",
			  "url": "https://leetcode.com/problems/merge-intervals",
			  "difficulty": "Medium"
			},
			{
			  "title": "Minimum Number of Arrows to Burst Balloons",
			  "url": "https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons",
			  "difficulty": "Medium"
			},
			{
			  "title": "Non-overlapping Intervals",
			  "url": "https://leetcode.com/problems/non-overlapping-intervals",
			  "difficulty": "Medium"
			},
			{
			  "title": "Task Scheduler",
			  "url": "https://leetcode.com/problems/task-scheduler",
			  "difficulty": "Medium"
			},
			{
			  "title": "Meeting Rooms",
			  "url": "https://leetcode.com/problems/meeting-rooms/",
			  "difficulty": "Medium"
			},
			{
			  "title": "Meeting Rooms II",
			  "url": "https://leetcode.com/problems/meeting-rooms-ii/",
			  "difficulty": "Medium"
			}
		  ]
		},
		{
		  "title": "K-way merge",
		  "problems": [
			{
			  "title": "Find K Pairs with Smallest Sums",
			  "url": "https://leetcode.com/problems/find-k-pairs-with-smallest-sums",
			  "difficulty": "Medium"
			},
			{
			  "title": "Kth Smallest Element in a Sorted Matrix",
			  "url": "https://leetcode.com/problems/kth-smallest-element-in-a-sorted-matrix",
			  "difficulty": "Medium"
			},
			{
			  "title": "Merge Two Sorted Lists",
			  "url": "https://leetcode.com/problems/merge-two-sorted-lists",
			  "difficulty": "Easy"
			},
			{
			  "title": "Merge k Sorted Lists",
			  "url": "https://leetcode.com/problems/merge-k-sorted-lists",
			  "difficulty": "Hard"
			},
			{
			  "title": "Smallest Range Covering Elements from K Lists",
			  "url": "https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists",
			  "difficulty": "Hard"
			}
		  ]
		},
		{
		  "title": "Backtracking",
		  "problems": [
			{
			  "title": "Combination Sum",
			  "url": "https://leetcode.com/problems/combination-sum",
			  "difficulty": "Medium"
			},
			{
			  "title": "Combination Sum II",
			  "url": "https://leetcode.com/problems/combination-sum-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Combination Sum III",
			  "url": "https://leetcode.com/problems/combination-sum-iii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Combinations",
			  "url": "https://leetcode.com/problems/combinations",
			  "difficulty": "Medium"
			},
			{
			  "title": "Generate Parentheses",
			  "url": "https://leetcode.com/problems/generate-parentheses",
			  "difficulty": "Medium"
			},
			{
			  "title": "Letter Case Permutation",
			  "url": "https://leetcode.com/problems/letter-case-permutation",
			  "difficulty": "Medium"
			},
			{
			  "title": "Letter Combinations of a Phone Number",
			  "url": "https://leetcode.com/problems/letter-combinations-of-a-phone-number",
			  "difficulty": "Medium"
			},
			{
			  "title": "N-Queens",
			  "url": "https://leetcode.com/problems/n-queens",
			  "difficulty": "Hard"
			},
			{
			  "title": "Palindrome Partitioning",
			  "url": "https://leetcode.com/problems/palindrome-partitioning",
			  "difficulty": "Medium"
			},
			{
			  "title": "Permutations",
			  "url": "https://leetcode.com/problems/permutations",
			  "difficulty": "Medium"
			},
			{
			  "title": "Permutations II",
			  "url": "https://leetcode.com/problems/permutations-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Subsets",
			  "url": "https://leetcode.com/problems/subsets",
			  "difficulty": "Medium"
			},
			{
			  "title": "Subsets II",
			  "url": "https://leetcode.com/problems/subsets-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Sudoku Solver",
			  "url": "https://leetcode.com/problems/sudoku-solver",
			  "difficulty": "Hard"
			},
			{
			  "title": "Target Sum",
			  "url": "https://leetcode.com/problems/target-sum",
			  "difficulty": "Medium"
			}
		  ]
		}
	  ]
	},
	{
	  "topic": "&#127876 Trees and Graphs",
	  "subtopics": [
		{
		  "title": "Tree BFS",
		  "problems": [
			{
			  "title": "All Nodes Distance K in Binary Tree",
			  "url": "https://leetcode.com/problems/all-nodes-distance-k-in-binary-tree",
			  "difficulty": "Medium"
			},
			{
			  "title": "Average of Levels in Binary Tree",
			  "url": "https://leetcode.com/problems/average-of-levels-in-binary-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Binary Tree Level Order Traversal",
			  "url": "https://leetcode.com/problems/binary-tree-level-order-traversal",
			  "difficulty": "Medium"
			},
			{
			  "title": "Binary Tree Level Order Traversal II",
			  "url": "https://leetcode.com/problems/binary-tree-level-order-traversal-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Binary Tree Right Side View",
			  "url": "https://leetcode.com/problems/binary-tree-right-side-view",
			  "difficulty": "Medium"
			},
			{
			  "title": "Binary Tree Zigzag Level Order Traversal",
			  "url": "https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal",
			  "difficulty": "Medium"
			},
			{
			  "title": "Minimum Depth of Binary Tree",
			  "url": "https://leetcode.com/problems/minimum-depth-of-binary-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Number of Islands",
			  "url": "https://leetcode.com/problems/number-of-islands",
			  "difficulty": "Medium"
			},
			{
			  "title": "Populating Next Right Pointers in Each Node",
			  "url": "https://leetcode.com/problems/populating-next-right-pointers-in-each-node",
			  "difficulty": "Medium"
			},
			{
			  "title": "Populating Next Right Pointers in Each Node II",
			  "url": "https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii",
			  "difficulty": "Medium"
			}
		  ]
		},
		{
		  "title": "Tree DFS",
		  "problems": [
			{
			  "title": "Binary Tree Maximum Path Sum",
			  "url": "https://leetcode.com/problems/binary-tree-maximum-path-sum",
			  "difficulty": "Hard"
			},
			{
			  "title": "Construct Binary Tree from Preorder and Inorder Traversal",
			  "url": "https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal",
			  "difficulty": "Medium"
			},
			{
			  "title": "Diameter of Binary Tree",
			  "url": "https://leetcode.com/problems/diameter-of-binary-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Implement Trie (Prefix Tree)",
			  "url": "https://leetcode.com/problems/implement-trie-prefix-tree",
			  "difficulty": "Medium"
			},
			{
			  "title": "Invert Binary Tree",
			  "url": "https://leetcode.com/problems/invert-binary-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Kth Smallest Element in a BST",
			  "url": "https://leetcode.com/problems/kth-smallest-element-in-a-bst",
			  "difficulty": "Medium"
			},
			{
			  "title": "Lowest Common Ancestor of a Binary Search Tree",
			  "url": "https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Lowest Common Ancestor of a Binary Tree",
			  "url": "https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree",
			  "difficulty": "Medium"
			},
			{
			  "title": "Maximum Binary Tree",
			  "url": "https://leetcode.com/problems/maximum-binary-tree",
			  "difficulty": "Medium"
			},
			{
			  "title": "Maximum Depth of Binary Tree",
			  "url": "https://leetcode.com/problems/maximum-depth-of-binary-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Maximum Width of Binary Tree",
			  "url": "https://leetcode.com/problems/maximum-width-of-binary-tree",
			  "difficulty": "Medium"
			},
			{
			  "title": "Merge Two Binary Trees",
			  "url": "https://leetcode.com/problems/merge-two-binary-trees",
			  "difficulty": "Easy"
			},
			{
			  "title": "Path Sum",
			  "url": "https://leetcode.com/problems/path-sum",
			  "difficulty": "Easy"
			},
			{
			  "title": "Path Sum II",
			  "url": "https://leetcode.com/problems/path-sum-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Path Sum III",
			  "url": "https://leetcode.com/problems/path-sum-iii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Same Tree",
			  "url": "https://leetcode.com/problems/same-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Serialize and Deserialize Binary Tree",
			  "url": "https://leetcode.com/problems/serialize-and-deserialize-binary-tree",
			  "difficulty": "Hard"
			},
			{
			  "title": "Subtree of Another Tree",
			  "url": "https://leetcode.com/problems/subtree-of-another-tree",
			  "difficulty": "Easy"
			},
			{
			  "title": "Validate Binary Search Tree",
			  "url": "https://leetcode.com/problems/validate-binary-search-tree",
			  "difficulty": "Medium"
			},
			{
			  "title": "Word Search II",
			  "url": "https://leetcode.com/problems/word-search-ii",
			  "difficulty": "Hard"
			}
		  ]
		},
		{
		  "title": "Topological Sorting",
		  "problems": [
			{
			  "title": "Course Schedule",
			  "url": "https://leetcode.com/problems/course-schedule",
			  "difficulty": "Medium"
			},
			{
			  "title": "Course Schedule II",
			  "url": "https://leetcode.com/problems/course-schedule-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Minimum Height Trees",
			  "url": "https://leetcode.com/problems/minimum-height-trees",
			  "difficulty": "Medium"
			}
		  ]
		},
                {
                  "title": "Trie",
                  "problems": [
                        {
                           "title": "Implement Trie (Prefix Tree)",
                           "url": "https://leetcode.com/problems/implement-trie-prefix-tree/",
                           "difficulty": "Medium"
                        },
                        {
                           "title": "Longest Word in Dictionary",
                           "url": "https://leetcode.com/problems/longest-word-in-dictionary/",
                           "difficulty": "Medium"
                        },
                        {
                           "title": "Maximum XOR of Two Numbers in an Array",
                           "url": "https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/",
                           "difficulty": "Medium"
                        },
                        {
                           "title": "Word Search II",
                           "url": "https://leetcode.com/problems/word-search-ii/",
                           "difficulty": "Hard"
                        },
                        {
                           "title": "Concatenated Words",
                           "url": "https://leetcode.com/problems/concatenated-words/",
                           "difficulty": "Hard"
                        }
                  ]
                },
		{
		  "title": "Graph Traversal",
		  "problems": [
			{
			  "title": "Clone Graph",
			  "url": "https://leetcode.com/problems/clone-graph",
			  "difficulty": "Medium"
			},
			{
			  "title": "Course Schedule",
			  "url": "https://leetcode.com/problems/course-schedule",
			  "difficulty": "Medium"
			},
			{
			  "title": "Number of Islands",
			  "url": "https://leetcode.com/problems/number-of-islands",
			  "difficulty": "Medium"
			},
			{
			  "title": "Pacific Atlantic Water Flow",
			  "url": "https://leetcode.com/problems/pacific-atlantic-water-flow",
			  "difficulty": "Medium"
			}
		  ]
		},
		{
		  "title": "2 Heaps",
		  "problems": [
			{
			  "title": "Find Median from Data Stream",
			  "url": "https://leetcode.com/problems/find-median-from-data-stream",
			  "difficulty": "Hard"
			},
			{
			  "title": "IPO",
			  "url": "https://leetcode.com/problems/ipo",
			  "difficulty": "Hard"
			},
			{
			  "title": "Sliding Window Median",
			  "url": "https://leetcode.com/problems/sliding-window-median",
			  "difficulty": "Hard"
			}
		  ]
		},
		{
		  "title": "Top K elements",
		  "problems": [
			{
			  "title": "Course Schedule III",
			  "url": "https://leetcode.com/problems/course-schedule-iii",
			  "difficulty": "Hard"
			},
			{
			  "title": "Find K Closest Elements",
			  "url": "https://leetcode.com/problems/find-k-closest-elements",
			  "difficulty": "Medium"
			},
			{
			  "title": "K Closest Points to Origin",
			  "url": "https://leetcode.com/problems/k-closest-points-to-origin",
			  "difficulty": "Medium"
			},
			{
			  "title": "Kth Largest Element in an Array",
			  "url": "https://leetcode.com/problems/kth-largest-element-in-an-array",
			  "difficulty": "Medium"
			},
			{
			  "title": "Kth Smallest Element in a BST",
			  "url": "https://leetcode.com/problems/kth-smallest-element-in-a-bst",
			  "difficulty": "Medium"
			},
			{
			  "title": "Maximum Frequency Stack",
			  "url": "https://leetcode.com/problems/maximum-frequency-stack",
			  "difficulty": "Hard"
			},
			{
			  "title": "Reorganize String",
			  "url": "https://leetcode.com/problems/reorganize-string",
			  "difficulty": "Medium"
			},
			{
			  "title": "Sort Characters By Frequency",
			  "url": "https://leetcode.com/problems/sort-characters-by-frequency",
			  "difficulty": "Medium"
			},
			{
			  "title": "Top K Frequent Elements",
			  "url": "https://leetcode.com/problems/top-k-frequent-elements",
			  "difficulty": "Medium"
			}
		  ]
		}
	  ]
	},
	{
	  "topic": "&#128640 Recursion and DP",
	  "subtopics": [
		{
		  "title": "Dynamic Programming",
		  "problems": [
			{
			  "title": "Best Time to Buy and Sell Stock",
			  "url": "https://leetcode.com/problems/best-time-to-buy-and-sell-stock",
			  "difficulty": "Easy"
			},
			{
			  "title": "Best Time to Buy and Sell Stock with Cooldown",
			  "url": "https://leetcode.com/problems/best-time-to-buy-and-sell-stock-with-cooldown",
			  "difficulty": "Medium"
			},
			{
			  "title": "Climbing Stairs",
			  "url": "https://leetcode.com/problems/climbing-stairs",
			  "difficulty": "Easy"
			},
			{
			  "title": "Coin Change",
			  "url": "https://leetcode.com/problems/coin-change",
			  "difficulty": "Medium"
			},
			{
			  "title": "Combination Sum IV",
			  "url": "https://leetcode.com/problems/combination-sum-iv",
			  "difficulty": "Medium"
			},
			{
			  "title": "Counting Bits",
			  "url": "https://leetcode.com/problems/counting-bits",
			  "difficulty": "Easy"
			},
			{
			  "title": "Decode Ways",
			  "url": "https://leetcode.com/problems/decode-ways",
			  "difficulty": "Medium"
			},
			{
			  "title": "House Robber",
			  "url": "https://leetcode.com/problems/house-robber",
			  "difficulty": "Medium"
			},
			{
			  "title": "House Robber II",
			  "url": "https://leetcode.com/problems/house-robber-ii",
			  "difficulty": "Medium"
			},
			{
			  "title": "Jump Game",
			  "url": "https://leetcode.com/problems/jump-game",
			  "difficulty": "Medium"
			},
			{
			  "title": "Longest Increasing Subsequence",
			  "url": "https://leetcode.com/problems/longest-increasing-subsequence",
			  "difficulty": "Medium"
			},
			{
			  "title": "Longest Palindromic Substring",
			  "url": "https://leetcode.com/problems/longest-palindromic-substring",
			  "difficulty": "Medium"
			},
			{
			  "title": "Maximum Product Subarray",
			  "url": "https://leetcode.com/problems/maximum-product-subarray",
			  "difficulty": "Medium"
			},
			{
			  "title": "Maximum Subarray",
			  "url": "https://leetcode.com/problems/maximum-subarray",
			  "difficulty": "Easy"
			},
			{
			  "title": "Number of Longest Increasing Subsequence",
			  "url": "https://leetcode.com/problems/number-of-longest-increasing-subsequence",
			  "difficulty": "Medium"
			},
			{
			  "title": "Palindromic Substrings",
			  "url": "https://leetcode.com/problems/palindromic-substrings",
			  "difficulty": "Medium"
			},
			{
			  "title": "Partition Equal Subset Sum",
			  "url": "https://leetcode.com/problems/partition-equal-subset-sum",
			  "difficulty": "Medium"
			},
			{
			  "title": "Partition to K Equal Sum Subsets",
			  "url": "https://leetcode.com/problems/partition-to-k-equal-sum-subsets",
			  "difficulty": "Medium"
			},
			{
			  "title": "Range Sum Query - Immutable",
			  "url": "https://leetcode.com/problems/range-sum-query-immutable",
			  "difficulty": "Easy"
			},
			{
			  "title": "Unique Paths",
			  "url": "https://leetcode.com/problems/unique-paths",
			  "difficulty": "Medium"
			},
			{
			  "title": "Word Break",
			  "url": "https://leetcode.com/problems/word-break",
			  "difficulty": "Medium"
			}
		  ]
		}
	  ]
	}
  ]