Search Insert Position

题目描述：

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

二分法

思路比较简单了，直接上代码

public class Solution {
public int searchInsert(int[] nums, int target) {
if(nums.length==0)
return 0;
return binarySearch(nums, 0, nums.length-1, target);
}

public int binarySearch(int[] nums,int left,int right,int target){
if(left==right){
if(nums[left]>=target)
return left;
else
return left+1;
}
int mid=(left+right)/2;
if(target==nums[mid]){
return mid;
}else if(target>nums[mid]){
return binarySearch(nums, mid+1, right, target);
}else if(target<nums[mid]){
return binarySearch(nums, left, mid, target);
}
return 0;
}
}