Submission #845324

#	Time	Username	Problem	Language	Result	Execution time	Memory
845324		vjudge1	Three Friends (BOI14_friends)	C++17	100 / 100	11 ms	10044 KiB

friends

#include <bits/stdc++.h>
#define ll long long
#define ld long double

using namespace std;

const int N = 1 << 20;
const int INF = INT_MAX;
const int mod = 1e9+7;

int n;
string a1,b1,s;
set<string> ans;

bool check(string a, string b) {
    for(int i = 0, j = 0, cnt = 0; i < a.size() ; i++) {
        if(a[i] != b[j] && cnt == 0) {
            cnt++;
            i--;
        }
        else if(a[i] != b[j]) {
            return false;
        }
        j++;
    }
    return true;
}

signed main()
{
    if (fopen("solve.inp", "r")) {
        freopen("solve.inp", "r", stdin);
        freopen("solve.out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> s;
    if(n%2 == 0) {
        cout << "NOT POSSIBLE";
        return 0;
    }
    a1 = s.substr(0,n/2);
    b1 = s.substr(n/2);
    if(check(a1,b1)) {
        ans.insert(a1);
    }
    a1 = s.substr(n/2+1);
    b1 = s.substr(0,n/2+1);
    if(check(a1,b1)) {
        ans.insert(a1);
    }
    if(ans.size() == 0) {
        cout << "NOT POSSIBLE";
    }
    else if(ans.size() > 1) {
        cout << "NOT UNIQUE";
    }
    else {
        cout << (*ans.begin());
    }
    return 0;
}

Compilation message (stderr)

friends.cpp: In function 'bool check(std::string, std::string)':
friends.cpp:16:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |     for(int i = 0, j = 0, cnt = 0; i < a.size() ; i++) {
      |                                    ~~^~~~~~~~~~
friends.cpp: In function 'int main()':
friends.cpp:32:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen("solve.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
friends.cpp:33:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         freopen("solve.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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