Submission #84689

#	Time	Username	Problem	Language	Result	Execution time	Memory
84689		teomrn	Three Friends (BOI14_friends)	C++14	100 / 100	85 ms	25308 KiB

friends

#include <bits/stdc++.h>
using namespace std;

string ans;
bool uniq;

void proc(string a, string b)
{
    if (a.size() < b.size())
        swap(a, b);
    char c = 0;
    int p = 0;
    for (auto i : a) {
        if (p == b.size() || b[p] != i) {
            if (c)
                return;
            c = i;
            p--;
        }
        p++;
    }
    if (c) {
        if (!ans.empty() && ans != b)
            uniq = 1;
        ans = b;
    }
}

int main()
{
    int l;
    cin >> l;
    string s;
    cin >> s;

    if (l % 2 == 0) {
        cout << "NOT POSSIBLE\n";
        return 0;
    }
    proc(s.substr(0, l / 2), s.substr(l / 2, l / 2 + 1));
    proc(s.substr(0, l / 2 + 1), s.substr(l / 2 + 1, l / 2));

    if (uniq)
        cout << "NOT UNIQUE\n";
    else if (ans.empty())
        cout << "NOT POSSIBLE\n";
    else
        cout << ans << '\n';

    return 0;
}

Compilation message (stderr)

friends.cpp: In function 'void proc(std::__cxx11::string, std::__cxx11::string)':
friends.cpp:14:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (p == b.size() || b[p] != i) {
             ~~^~~~~~~~~~~

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