题解 | 找x

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

int main() 
{
   int n;
   scanf("%d",&n);
   vector<int> vec(n);
   for(int i = 0; i < n;++i)
   {
    scanf("%d",&vec[i]);
   }
   int x;
   scanf("%d",&x);
   int idx;
   for(idx = 0; idx < n ; ++idx)
   {
    if(vec[idx] == x)
    {
        printf("%d\n",idx);
        return 0;
    }
   }
   if(idx == n)
   {
        printf("-1\n");
   }
   return 0;
}