Search Insert Position - LeetCode

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

You may assume no duplicates in the array.

Here are few examples.
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

 

简单的binary search的变形。

已犯错误：1. 由于不是完全的binary search，所以target比中间元素小的时候，r不应该移到m-1, 而是应该移到m

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