LintCode 搜索插入位置题目分析代码

public class Solution {
    /** 
     * param A : an integer sorted array
     * param target :  an integer to be inserted
     * return : an integer
     */
    public int searchInsert(int[] A, int target) {
        // write your code here
        if(A.length == 0)
            return 0;
        if(A == null)
            return -1;
        int lo = 0;
        int hi = A.length - 1;
        int mid;
        while(lo <= hi)
        {
            mid = (hi-lo)/2 + lo;
            if(target < A[mid])
                hi = mid-1;
            else if(target > A[mid])
                lo = mid+1;
            else
                return mid;
        }
        return lo;
    }
}