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

 

题目大意：给一个有序数组（无重复元素），一个数字，检查数字是否出现在数组中，出现就返回数组下标，否则返回应插入的位置下标。

解题思路：二分。

public class Solution {

    public int searchInsert(int[] nums, int target) {

        if(nums==null||nums.length==0){

            return 0;

        }

        int low = 0,high = nums.length-1;

        while(low<=high){

            int mid = (low+high)>>1;

            if(nums[mid]==target){

                return mid;

            }

            if(nums[mid]>target){

                high=mid-1;

            }else{

                low=mid+1;

            }

        }

        return low;

    }

}