题解 | 找x
#include <bits/stdc++.h>
using namespace std;
int main(){
int n;
while (cin>>n) {
map<int,int>a;
for(int i=0;i<n;i++){
int y;cin>>y;
a[y]=i+1;
}
int x;cin>>x;
if(a[x]==0)cout<<-1<<endl;
else cout<<a[x]-1<<endl;
}
}
用map搜更快速
