35、Search Insert Position

二分搜索算法实现

最新推荐文章于 2020-06-11 09:19:32 发布

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本文介绍了一种在已排序数组中查找目标值或确定插入位置的二分搜索算法实现。该算法适用于没有重复元素的情况，并提供了几个示例来说明其工作原理。

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

Array Binary Search

 int searchInsert(int A[], int n, int target) {
        //此题比较简单，顺序遍历是好的，但是对于有序数组来说，我们尝试使用二分搜索
        int low  = 0, high = n, mid;
        while (low < high)
        {
            mid = (low + high) / 2;
            if (A[mid] >= target)
                high = mid;
            else 
                low = mid + 1;
        }
        if (A[mid] >= target)
            return mid;
        else
            return mid + 1;
            
    }