题解 | 找x

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <vector>
using namespace std;
int main() {
	int n,x;
	scanf("%d", &n);
	vector<int> vec(n);
	for (int i = 0; i < n; ++i) {
		scanf("%d", &vec[i]);
	}
	scanf("%d", &x);
	int idx;
	for (idx = 0; idx < n; ++idx) {
		if (vec[idx] == x) {
			printf("%d", idx);
			break;
		}
	}
	if (idx == n) {
		printf("-1");
	}
	return 0;
}