题目：牛客网

解题思路：

二分查找

 

public class Solution {
    public int searchInsert(int[] A, int target) {
        int low = 0;
        int high = A.length-1;
        while(low<=high){
        	int mid = (low+high)/2;
        	if(target == A[mid]){
        		return mid;
        	}
        	else if(target < A[mid]){
        		high =mid-1;
        	}
        	else{
        		low = mid+1;
        	}
        }
        return low;
    }
}