Leetcode 88.merge-sorted-array——合并两个有序数组

Given two sorted integer arrays A and B, merge B into A as one sorted array.

Note: 
You may assume that A has enough space to hold additional elements from B. The number of elements initialized in A and B are m and n respectively.

 

归并排序

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        vector<int> v(m+n,0);
        int i=0,j=0,k=0;
        while(i<m&&j<n){
            if(A[i]<B[j])
                v[k++]=A[i++];
            else
                v[k++]=B[j++];
            
        }
        while(i<m){
            v[k++]=A[i++];
            
        }
        while(j<n){
            v[k++]=B[j++];
        }
        for(i=0;i<m+n;i++)
            A[i]=v[i];
    }
};

直接使用nums1的空间进行排序，从后向前依次merge

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