'Pascal's Triangle' soln

Author: joewnga

README.md

@@ -121,8 +121,8 @@ Note: Some solutions have multiple approaches implemented
 | 113 | [Path Sum II](https://leetcode.com/problems/path-sum-ii/) | [Solution](./leetcode/path_sum_ii.rs) | Medium |
 | 114 | [Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/) | [Solution](./leetcode/flatten_binary_tree.rs) | Medium |
 | 115 | [Distinct Subsequences](https://leetcode.com/problems/distinct-subsequences/) | [Solution](./leetcode/distinct_subsequences.rs) | Hard |
-| >116 | [Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/) | [Solution](./leetcode/populating_next_right_pointers.rs) | Medium |
-| 117 | [Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/) | [Solution](./leetcode/populating_next_right_pointers_ii.rs) | Medium |
+| x116 | [Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node/) | [Solution](./leetcode/populating_next_right_pointers.rs) | Medium |
+| x117 | [Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/) | [Solution](./leetcode/populating_next_right_pointers_ii.rs) | Medium |
 | 118 | [Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/) | [Solution](./leetcode/pascals_triangle.rs) | Easy |
 | 119 | [Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/) | [Solution](./leetcode/pascals_triangle_ii.rs) | Easy |
 | 120 | [Triangle](https://leetcode.com/problems/triangle/) | [Solution](./leetcode/triangle.rs) | Medium |

leetcode/pascals_triangle.rs

@@ -0,0 +1,53 @@
+/// 
+/// Problem: Pascal's Triangle
+/// 
+/// Given an integer numRows, return the first numRows of Pascal's triangle.
+/// 
+/// In Pascal's triangle, each number is the sum of the two numbers directly above it.
+/// 
+/// Example 1:
+/// Input: numRows = 5
+/// Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]
+/// 
+/// Example 2:
+/// Input: numRows = 1
+/// Output: [[1]]
+/// 
+/// Constraints:
+/// 1 <= numRows <= 30
+/// 
+
+// # Solution:
+// Time complexity: O(numRows²) 
+// Space complexity: O(numRows²) 
+
+impl Solution {
+    pub fn generate(num_rows: i32) -> Vec<Vec<i32>> {
+        let num_rows = num_rows as usize;
+       let mut result = Vec::with_capacity(num_rows);
+       
+       
+       result.push(vec![1]);
+       
+       
+       for i in 1..num_rows {
+           let prev_row = &result[i - 1];
+           let mut current_row = Vec::with_capacity(i + 1);
+           
+           
+           current_row.push(1);
+           
+           
+           for j in 1..i {
+               current_row.push(prev_row[j - 1] + prev_row[j]);
+           }
+           
+           
+           current_row.push(1);
+           
+           result.push(current_row);
+       }
+       
+       result
+    }
+}