PAT A1144 The Missing Number (20point(s))

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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 (≤10
​5
​​ ). 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

解答

#include<iostream>
#include<map>
#include<climits>
using namespace std;
int main() {
	int n, k;
	map<int, bool> mp;
	scanf("%d", &n);
	for (int i = 0; i < n; i++) {
		scanf("%d", &k);
		mp[k] = true;
	}
	for (int i = 1; i < INT_MAX; i+=1) {
		if (!mp[i]) {
			printf("%d", i);
			break;
		}
	}
	return 0;
}