【面試題 & LeetCode 88】 Merge Sorted Array

題目描述

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

Note:

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

思路

從後往前。

代碼

class Solution {
public:
    void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) {
        if (n == 0) return;
        int p1 = m-1;
        int p2 = n-1;
        int p = n+m-1;
        while(p1>=0 && p2>=0) {
            if (nums1[p1] > nums2[p2]) {
                nums1[p--] = nums1[p1--];
            }else nums1[p--] = nums2[p2--];
        }
        while(p1>=0) nums1[p--] = nums1[p1--];
        while(p2>=0) nums1[p--] = nums2[p2--];
        return;
    }
};