[LeetCode]Merge Sorted Array

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.

思考：3指针。从后往前遍历。

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        int i=m-1;
        int j=n-1;
        int k=m+n-1;
        while(k>=0)
        {
            if(i>=0&&A[i]>=B[j]) 
            {
                A[k]=A[i];
                i--;
                k--;
            }
            else if(j>=0&&A[i]<B[j])
            {
                A[k]=B[j];
                j--;
                k--;
            }
            if(i>=0&&j<0) return;
            if(i<0&&j>=0)
            {
                for(int p=0;p<=j;p++)
                {
                    A[p]=B[p];
                }
                return;
            }
        }
    }
};

2014-03-27 16:53:19

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        int i=m-1;
        int j=n-1;
        int k=m+n-1;
        while(i>=0&&j>=0)
        {
            if(A[i]>B[j]) A[k--]=A[i--];
            else A[k--]=B[j--];
        }
        //未考虑m=0的情况
        while(j>=0) A[k--]=B[j--];
    }
};