Submission #1037560

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037560		sleepntsheep	Thousands Islands (IOI22_islands)	C++17	6.75 / 100	28 ms	8284 KiB

islands

#include "islands.h"

#include <variant>
#include <vector>
using namespace std;

std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {
    vector<vector<int>> a(N);
    for (int i = 0; i < M; ++i)
        a[U[i]].push_back(i);

    if (N==2){
        if(a[0].size()>=2&&a[1].size()){
            int a1=a[0][0],a2=a[0][1],a3=a[1][0];
            return vector<int>{a1, a3, a2, a1, a3, a2};
        }
        return false;
    }else if(N<=400){

        static int id[401][401];
        for(int i=0;i<M;++i)id[U[i]][V[i]]=i;
        int a1=id[0][1],a2=id[1][0],a3=id[1][2],a4=id[2][1],a5=id[5][6],a6=id[6][5];
        return vector<int>{a1,a3,a5,a6,a4,a2,a5,a3,a1,a2,a4,a6};
    }
}

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:9:28: warning: control reaches end of non-void function [-Wreturn-type]
    9 |     vector<vector<int>> a(N);
      |                            ^

• Subtask 1: 5 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45