1064. Fixed Point 不动点
2022年3月7日
- 作者: 负雪明烛
- id: fuxuemingzhu
- 个人博客:http://fuxuemingzhu.cn/
@TOC
题目地址:https://leetcode-cn.com/problems/fixed-point/
题目描述
Given an array A of distinct integers sorted in ascending order, return the smallest index i that satisfies A[i] == i
. Return -1 if no such i exists.
Example 1:
Input: [-10,-5,0,3,7]
Output: 3
Explanation:
For the given array, A[0] = -10, A[1] = -5, A[2] = 0, A[3] = 3, thus the output is 3.
Example 2:
Input: [0,2,5,8,17]
Output: 0
Explanation:
A[0] = 0, thus the output is 0.
Example 3:
Input: [-10,-5,3,4,7,9]
Output: -1
Explanation:
There is no such i that A[i] = i, thus the output is -1.
Note:
1 <= A.length < 10^4
-10^9 <= A[i] <= 10^9
题目大意
给定已经按升序排列、由不同整数组成的数组 A,返回满足 A[i] == i 的最小索引 i。如果不存在这样的 i,返回 -1。
解题方法
暴力求解
从头遍历一遍即可。
C++代码如下:
class Solution {
public:
int fixedPoint(vector<int>& A) {
const int N = A.size();
for (int i = 0; i < N; ++i) {
if (A[i] == i)
return i;
}
return -1;
}
};
日期
2019 年 9 月 18 日 —— 今日又是九一八