Merge Sorted Array 题解

题目来源：https://leetcode.com/problems/merge-sorted-array/description/

Description

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

Note:

You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1 and nums2 are m and n respectively.

Solution

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        int i = m - 1, j = n - 1, k = m + n - 1;
        while (i >= 0 && j >= 0) {
            nums1[k--] = nums1[i] >= nums2[j] ? nums1[i--] : nums2[j--];
        }
        while (j >= 0) {
            nums1[k--] = nums2[j--];
        }
    }
};

解题描述

这道题题意是，给出两个排好序的数组nums1和nums2，分别包含m、n个数字，nums1总的空间不小于m + n，要求合并两个数组，将结果存在nums1中。也就是说，空余的空间一开始是在nums1数组的尾部，算法就是从大到小进行归并，将结果依次插入到nums1尾部即可，这样就不需要额外的空间保存归并的结果。