mergeSortedArray.js

/**
 * @param {number[]} nums1
 * @param {number} m
 * @param {number[]} nums2
 * @param {number} n
 * @return {void} Do not return anything, modify nums1 in-place instead.
 */
var merge = function (nums1, m, nums2, n) {
  let p1 = m - 1;
  let p2 = n - 1;
  let p = m + n - 1;
  while (p1 >= 0 && p2 >= 0) {
    if (nums1[p1] > nums2[p2]) {
      nums1[p] = nums1[p1];
      p1--;
    } else {
      nums1[p] = nums2[p2];
      p2--;
    }
    p--;
  }

  while (p2 >= 0) {
    nums1[p] = nums2[p2];
    p2--;
    p--;
  }
};


// Example 1:
//
//Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
//Output: [1,2,2,3,5,6]
//Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
//The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.

let nums1 = [1, 2, 3, 0, 0, 0];
let m = 3;
let nums2 = [2, 5, 6];
let n = 3;

merge(nums1, m, nums2, n);
console.log(nums1);

//Example 2:
//
//Input: nums1 = [1], m = 1, nums2 = [], n = 0
//Output: [1]
//Explanation: The arrays we are merging are [1] and [].
//The result of the merge is [1].

nums1 = [1];
m = 1;
nums2 = [];
n = 0;

merge(nums1, m, nums2, n);
console.log(nums1);

//Example 3:
//
//Input: nums1 = [0], m = 0, nums2 = [1], n = 1
//Output: [1]
//Explanation: The arrays we are merging are [] and [1].
//The result of the merge is [1].
//Note that because m = 0, there are no elements in nums1.
// The 0 is only there to ensure the merge result can fit in nums1.

nums1 = [];
m = 0;
nums2 = [1];
n = 1;

merge(nums1, m, nums2, n);
console.log(nums1);


nums1 = [2, 0];
m = 1;
nums2 = [1];
n = 1;

merge(nums1, m, nums2, n);
console.log(nums1);