Submission #736872

#	Time	Username	Problem	Language	Result	Execution time	Memory
736872		onlk97	Thousands Islands (IOI22_islands)	C++17	10 / 100	60 ms	49432 KiB

islands

#include "islands.h"

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

vector <int> bruh[1010][1010];
std::variant<bool, std::vector<int>> find_journey(int N, int M, std::vector<int> U, std::vector<int> V) {
    if (N==2){
        vector <int> a,b;
        for (int i=0; i<M; i++){
            if (!U[i]) a.push_back(i);
            else b.push_back(i);
        } 
        if (a.size()>=2&&b.size()){
            vector <int> ans;
            ans.push_back(a[0]); ans.push_back(b[0]); ans.push_back(a[1]);
            ans.push_back(a[0]); ans.push_back(b[0]); ans.push_back(a[1]);
            return ans;
        }
        return false;
    }
    bool subtask2=(N<=400);
    bool subtask3=(N<=1000);
    if (N<=1000){
        for (int i=0; i<M; i++){
            bruh[U[i]][V[i]].push_back(i);
        }
        for (int i=0; i<N; i++){
            for (int j=0; j<N; j++){
                if (i==j) continue;
                if (bruh[i][j].size()!=1) subtask2=0;
            }
        }
        for (int i=0; i<N; i++){
            for (int j=i+1; j<N; j++){
                if (bruh[i][j].size()!=bruh[j][i].size()) subtask3=0;
            }
        }
    }
    if (subtask2){
        vector <int> ans;
        ans.push_back(bruh[0][1][0]);
        ans.push_back(bruh[1][0][0]);
        ans.push_back(bruh[0][2][0]);
        ans.push_back(bruh[2][0][0]);
        ans.push_back(bruh[1][0][0]);
        ans.push_back(bruh[0][1][0]);
        ans.push_back(bruh[2][0][0]);
        ans.push_back(bruh[0][2][0]);
        return ans;
    }
    
}

Compilation message (stderr)

islands.cpp: In function 'std::variant<bool, std::vector<int, std::allocator<int> > > find_journey(int, int, std::vector<int>, std::vector<int>)':
islands.cpp:25:10: warning: variable 'subtask3' set but not used [-Wunused-but-set-variable]
   25 |     bool subtask3=(N<=1000);
      |          ^~~~~~~~
islands.cpp:55:1: warning: control reaches end of non-void function [-Wreturn-type]
   55 | }
      | ^

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45