Submission #398735

#	Time	Username	Problem	Language	Result	Execution time	Memory
398735		YaserFaisal	Three Friends (BOI14_friends)	C++17	0 / 100	1099 ms	18716 KiB

friends

#include <bits/stdc++.h>
 
using namespace std ;
 
//#define int long long 
int MOD = 1e9+7 ;
int freq[200] ;
vector < int > v[200] ;

int32_t main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int n ; cin >> n ; 
    string s ; cin >> s ; 
	for ( int i = 0 ; i < n ; i++ )
    {
        freq[s[i]]++ ;
        v[s[i]].push_back(i) ;
    }
    char x ;
    int odd = 0 ; 
    for ( int i = 'A' ; i <= 'Z' ; i++ )
    {
        if ( freq[i] % 2 )
        {
            odd++ ;
            x = i ;
        }
    }
    if ( odd > 1 || n % 2 == 0 || odd == 0 )
    {
        cout << "NOT POSSIBLE\n" ;
        return 0 ;
    }
    string ans = "-" ;
    for ( int i = 0 ; i < v[x].size() ; i++ )
    {
        string g = s ; 
        g.erase(g.begin()+v[x][i]) ;
        string a = (g.substr(0,n/2)) , b = (g.substr(n/2,n/2)) ;
        if ( a == b )
        {
            if ( ans != "-" )
            {
                cout << "NOT UNIQUE\n" ;
                return 0 ;
            }
            ans = a ;
        }
    }
    if ( ans == "-" ) ans = "NOT POSSIBLE" ;
    cout << ans << "\n" ;
}

Compilation message (stderr)

friends.cpp: In function 'int32_t main()':
friends.cpp:17:18: warning: array subscript has type 'char' [-Wchar-subscripts]
   17 |         freq[s[i]]++ ;
      |                  ^
friends.cpp:18:15: warning: array subscript has type 'char' [-Wchar-subscripts]
   18 |         v[s[i]].push_back(i) ;
      |               ^
friends.cpp:36:29: warning: array subscript has type 'char' [-Wchar-subscripts]
   36 |     for ( int i = 0 ; i < v[x].size() ; i++ )
      |                             ^
friends.cpp:36:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |     for ( int i = 0 ; i < v[x].size() ; i++ )
      |                       ~~^~~~~~~~~~~~~
friends.cpp:39:29: warning: array subscript has type 'char' [-Wchar-subscripts]
   39 |         g.erase(g.begin()+v[x][i]) ;
      |                             ^
friends.cpp:20:10: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   20 |     char x ;
      |          ^

• Subtask 1: 0 / 35
• Subtask 2: 0 / 65