[leetcode]Search Insert Position

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Search Insert Position 

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

演算法思路：

最最基本的二分尋找法，找不到則返回left指標。

代碼如下：

 1 public class Solution { 2     public int searchInsert(int[] a, int target) { 3         if(a == null || a.length == 0) return 0; 4         int begin = 0, end = a.length - 1; 5         while(begin <= end){ 6             int mid = (begin + end) >> 1; 7             if(a[mid] == target){ 8                 return mid; 9             }else if(a[mid] > target){10                 end = mid - 1;11             }else{12                 begin = mid + 1;13             }14         }15         return begin;16     }17 }