Submission #715040

#	Time	Username	Problem	Language	Result	Execution time	Memory
715040		keystone	Logičari (COCI21_logicari)	C++14	10 / 110	79 ms	6964 KiB

Main

#include<iostream>
#include<vector>
#include<algorithm>
#define ll long long
using namespace std;

int main(){
    int n;
    cin>>n;
    vector<vector<int>> graph(n);
    int a,b;
    for(int i=0;i<n;i++){
        cin>>a>>b;
        graph[a-1].push_back(b-1);
        graph[b-1].push_back(a-1);
    }
    if(n<=20){
        int ans=1e9;
        for(int i=0;i<(1<<n);i++){
            for(int j=0;j<n;j++){
                int cnt=0;
                for(auto x:graph[j]){
                    if(((1<<x)&i)>0){
                        cnt++;
                    }
                }
                if(cnt!=1) break;
                if(j==n-1){
                    cnt=0;
                    for(int k=0;k<n;k++){
                        if(((1<<k)&i)>0) cnt++;
                    }
                    ans=min(ans,cnt);
                }
            }
        }
        if(ans==1e9) cout<<-1<<"\n";
        else cout<<ans<<"\n";
        return 0;
    }
    if(n%4!=0) {
        cout<<-1<<"\n";
        return 0;
    }
    int blue = n/2;
    int red = n/2;
    vector<bool> has_blue(n, false);
    for (int i = 0; i < n; i++) {
        int blue_cnt = 0;
        for (int j = 0; j < graph[i].size(); j++) {
            if (has_blue[graph[i][j]]) {
                blue_cnt++;
            }
        }
        if (blue_cnt == 1) {
            blue--;
            has_blue[i] = true;
        }
        else {
            red--;
        }
    }
    if (blue < 0 || red < 0) {
        cout<<-1<<"\n";
    }
    else {
        cout<<blue<<"\n";
    }
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:50:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |         for (int j = 0; j < graph[i].size(); j++) {
      |                         ~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 40
• Subtask 4: 0 / 50