【PTA Advanced】1144 The Missing Number（C++）

目录

题目

Input Specification:

Output Specification:

Sample Input:

Sample Output:

思路

代码

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题目

Given N integers, you are supposed to find the smallest positive integer that is NOT in the given list.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (≤105). Then N integers are given in the next line, separated by spaces. All the numbers are in the range of int.

Output Specification:

Print in a line the smallest positive integer that is missing from the input list.

Sample Input:

10
5 -25 9 6 1 3 4 2 5 17

Sample Output:

7

思路

难度评级：⭐️

408算法题出到过这题

最小未出现的正整数一定在1~n+1之间

代码

#include <iostream>
#include <vector>using namespace std;int main(int argc, char** argv) {int n;cin>>n;vector<int> a(n+1);for(int i=0;i<n;i++) {int x;cin>>x;if(x>=1&&x<=n) a[x]=1;}int i;for(i=1;i<=n;i++) {if(a[i]==0) break;}cout<<i;return 0;
}