LeetCode刷题【Array】Search Insert Position

最新推荐文章于 2023-10-11 12:01:45 发布

最新推荐文章于 2023-10-11 12:01:45 发布 · 272 阅读

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本文介绍了一种在有序数组中查找目标值或确定插入位置的优化算法。通过二分查找的方法提高了查找效率，避免了顺序查找的局限性。

题目：

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

解决方案一： Runtime 7 ms

public class Solution {
    public int searchInsert(int[] nums, int target) {
        int size=nums.length;
        if(nums==null||nums[0]>target) return 0;
        for(int i=0;i<size;i++){
            if(nums[i]>=target)
                return i;
        }
        return size;
    }
}

解决方法二：（优化查找）

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

参考：

【1】https://leetcode.com/