LeetCode:Search Insert Position

二分查找算法实现元素插入位置

最新推荐文章于 2021-05-03 16:49:38 发布

转载最新推荐文章于 2021-05-03 16:49:38 发布 · 60 阅读

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原文链接：http://www.cnblogs.com/jessiading/p/3779973.html

本文介绍了一个使用二分查找算法来确定数组中目标值应该插入的位置以保持数组有序的方法。通过实现搜索插入函数，可以高效地找到目标值在已排序数组中的正确索引或插入位置。

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

其实就是二分查找后返回left值就是插入值。

public class Solution {
     public int searchInsert(int[] A, int target) {
        if(A == null || A.length == 0)return 0;
        int left = 0;
        int right = A.length - 1;
        int mid = (left + right)/2;
        while(left<=right)
        {
            if(A[mid] == target)
            {
                return mid;
            }
            else if(A[mid]<target)
            {
                left = mid + 1;
            }
            else
            {
                right = mid - 1;
            }
            mid = (left + right)/2;
        }
        return left;
    }
}

转载于:https://www.cnblogs.com/jessiading/p/3779973.html