88. Merge Sorted Array

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.

 

从后往前扫一遍

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