88. Merge Sorted Array

source: https://leetcode.com/problems/merge-sorted-array/

Question

You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.

Merge nums1 and nums2 into a single array sorted in non-decreasing order.

The final sorted array should not be returned by the function, but instead be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. nums2 has a length of n.

思路

两个数组，而且都是有序数组，要求O(m + n)时间复杂度，是比较典型的双指针的类型。

/**
 * @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) {
    nums1.splice(m, n);
    let p1 = 0;
    let p2 = 0;
    while (p2 < n) {
        const v = nums2[p2];
        while (nums1[p1] <= v && p1 < nums1.length) p1++;
        nums1.splice(p1, 0, v);
        p2++;
    }
    return nums1;
};

总结

比较典型简单的题目平时也可以练个手。