35. 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

解题方法

two points: low ans hight

mid = low + (high - low) / 2 : avoid overfloew

while(low + 1 < high) : left bias

    public int searchInsert(int[] nums, int target) {
         //Key word: Sorted array
        int low = 0, high = nums.length - 1;
        while( low + 1 < high){
            int mid = low + ( high - low) / 2;
            if(nums[mid] == target){
                return mid;
            }else if( nums[mid] < target){
                low = mid;        
            }else{
                high = mid;
            }
        }

        if( nums[low] >= target){
            return low;
        }else if(nums[high] >= target){
            return high;
        }else{
            return high + 1;
        }
    }