Search Insert Position

class Solution {public:    int searchInsert(int A[], int n, int target) {        if(target<=A[0])    return 0;        if(target>A[n-1])  return n;        if(target==A[n-1])  return n-1;        //二分查找        int left=0,right=n-1,mid=0;        while(left<=right)        {            mid=left+(right-left)/2;            if(A[mid]==target)            {                return mid;            }            else if(A[mid]<target)            {                if((mid+1)<n && A[mid+1]>target) return mid+1;                left=mid+1;            }            else            {                if((mid-1)>0 && A[mid-1]<target)   return mid;                right=mid-1;            }        }        return -2;//algorithm error    }};