substr超尾
#include<iostream>
#include<string>
#include<cstring>
#include<algorithm>
using namespace std;
int n;
int main()
{
scanf("%d\n", &n);
string ans;
for (int i = 0; i < n; i++)
{
string s;
getline(cin, s);
reverse(s.begin(), s.end());
if (i == 0)
{
ans = s;
continue;
}
else
{
for (int j = 0; j < min(ans.length(), ans.length()); j++)
{
if (ans[j] != s[j])
{
ans = ans.substr(0, j);
break;
}
}
}
}
reverse(ans.begin(), ans.end());
if (ans.length() == 0)printf("nai");
else cout << ans;
return 0;
}
