leetcode : Search Insert Position

最新推荐文章于 2021-05-03 16:49:38 发布

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最新推荐文章于 2021-05-03 16:49:38 发布

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/superzhaochao/p/6407246.html

本文介绍了一种在已排序数组中查找目标值并确定其插入位置的方法。通过二分查找算法，实现高效定位。提供了完整的Java代码示例，并考虑了边界情况。

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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

tag : binary search .

left < right - 1 目的是最终不会出现 left > right的情形。因此，结束时可能最终指针停留在两个元素上。

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

转载于:https://www.cnblogs.com/superzhaochao/p/6407246.html