[LeetCode]Search Insert Position

题目

Number: 35

Difficulty: Medium

Tags: Array, Binary Search

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.

[code][1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

题解

在有序数组寻找目标值，找到则返回下标，否则返回应当插入的位置。

典型的二分搜索题。二分查找关键在于边界的确定。

代码

[code]int searchInsert(vector<int>& nums, int target) {
    if(nums.empty())
        return 0;
    int l = 0, h = nums.size() - 1;
    while(l <= h)
    {
        int mid = l + ((h - l) >> 1);
        if(nums[mid] == target)
            return mid;
        else if(nums[mid] < target)
            l = mid + 1;
        else
            h = mid - 1;
    }
    return l;
}