Submission #832524

#	Time	Username	Problem	Language	Result	Execution time	Memory
832524		vjudge1	Three Friends (BOI14_friends)	C++17	100 / 100	47 ms	8144 KiB

friends

#include <iostream>
using namespace std;
int n;
bool canFirst, canSecond;
string s, t1, t2;
bool canAddLetter(const string &t) {
    bool added = false;
    for (int i = 0; i < t.size(); i++) {
        if (!added && t[i] != s[i]) added = true;
        if (added && t[i] != s[i + 1]) return false;
    }
    return true;
}
int main() {
    cin >> n >> s;
    if (n & 1) {
        n >>= 1;
        t1 = s.substr(0, n); t2 = s.substr(n + 1);
        canFirst = canAddLetter(t1 + t1); canSecond = canAddLetter(t2 + t2);
        if (canFirst && canSecond && t1 == t2) cout << t1;
        else if (canFirst && canSecond) cout << "NOT UNIQUE";
        else if (canFirst) cout << t1;
        else if (canSecond) cout << t2;
        else cout << "NOT POSSIBLE";
    }
    else cout << "NOT POSSIBLE";
    return 0;
}

Compilation message (stderr)

friends.cpp: In function 'bool canAddLetter(const string&)':
friends.cpp:8:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 |     for (int i = 0; i < t.size(); i++) {
      |                     ~~^~~~~~~~~~

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