题解 | 找x

//KY157 找x
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;
int n, x;
int main()
{
    while(cin>>n)
    {
        vector<int>v(n);
        for(int i=0;i<n;i++) cin>>v[i];
        cin>>x;
        vector<int>::iterator it;
        it=find(v.begin(), v.end(),x);
        if(it==v.end()) cout<<-1<<"\n";
        else cout<<it-v.begin()<<"\n";
    }
    return 0;
}