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 (size that is greater or equal to m + n) to hold additional elements from B. The number of elements initialized in A and B are m and n respectively.

考虑从后往前比较，这样就不会产生需要数据后移的问题了。时间复杂度O(n+m)

代码如下：

void merge(int A[], int m, int B[], int n) {
    int index, aindex,bindex;
    index = m+n-1;
    aindex = m-1;
    bindex = n-1;
    while(aindex >= 0 && bindex >= 0){
        if(A[aindex] > B[bindex]){
            A[index--] = A[aindex--];
        }else{
            A[index--] = B[bindex--];
        }
    }
    while(bindex >= 0)
        A[index--] = B[bindex--];
}

 

class Solution {
public:
    void merge(int A[], int m, int B[], int n) {
        int index = m + n - 1;
         int aIndex = m - 1;
         int bIndex = n - 1;
         while(0 <= aIndex && 0 <= bIndex)
         {
             if (B[bIndex] > A[aIndex])
             {
                 A[index--] = B[bIndex--];
             }
             else
             {
                 A[index--] = A[aIndex--];
             }
         }
         
         
         while(0 <= bIndex)
         {
             A[index--] = B[bIndex--];
         }
    }
};