题解 | #找x#

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    int target;
    vector<int> vec;
    while (cin >> n) { // 注意 while 处理多个 case
        vec.clear();
        int num;
        for (int i = 1; i <= n; i++) {
            cin >> num;
            vec.emplace_back(num);
        }
        cin >> target;
        //vector<int>::iterator
        vector<int>::iterator it = find(vec.begin(), vec.end(), target);
        if (it == vec.end()) {
            cout << -1 << endl;
        }
        else {
            cout << distance(vec.begin(), it) << endl;
        }
    }
}
// 64 位输出请用 printf("%lld")