leetcode 4

Author: geekplux

README.md

@@ -22,6 +22,7 @@
 - 92.Reverse Linked List II `medium` `linked list` [link](https://leetcode.com/problems/reverse-linked-list-ii/description/) [code](./leetcode/92.js)
 - 2.Add Two Numbers `medium` `linked list` [link](https://leetcode.com/problems/add-two-numbers/description/) [code](./leetcode/2.js)
 - 3.Longest Substring Without Repeating Characters `medium` `string` [link](https://leetcode.com/problems/longest-substring-without-repeating-characters/description/) [code](./leetcode/3.js)
+- 4.Median of Two Sorted Arrays `hard` `array` [link](https://leetcode.com/problems/median-of-two-sorted-arrays/description/) [code](./leetcode/4.js)
 
 ## lintcode
 

leetcode/4.js

@@ -0,0 +1,62 @@
+/*
+4. Median of Two Sorted Arrays
+
+
+There are two sorted arrays nums1 and nums2 of size m and n respectively.
+
+Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).
+
+You may assume nums1 and nums2 cannot be both empty.
+
+Example 1:
+
+nums1 = [1, 3]
+nums2 = [2]
+
+The median is 2.0
+
+
+Example 2:
+
+nums1 = [1, 2]
+nums2 = [3, 4]
+
+The median is (2 + 3)/2 = 2.5
+*/
+
+/**
+ * @param {number[]} nums1
+ * @param {number[]} nums2
+ * @return {number}
+ */
+var findMedianSortedArrays = function (nums1, nums2) {
+  const len = nums1.length + nums2.length;
+
+  let i = 0; j = 0;
+  let current, last;
+
+  while (i + j <= len / 2) {
+    last = current;
+
+    if (nums1[i] === undefined) {
+      current = nums2[j++];
+      continue;
+    }
+
+    if (nums2[j] === undefined) {
+      current = nums1[i++];
+      continue;
+    }
+
+    if (nums1[i] <= nums2[j]) {
+      current = nums1[i++];
+    } else {
+      current = nums2[j++];
+    }
+  }
+
+  return len % 2 == 0 ? (last + current) / 2 : current;
+};
+
+console.log(findMedianSortedArrays([1, 3], [2]));
+console.log(findMedianSortedArrays([1, 2], [3, 4]));