Submission #630925

#	Time	Username	Problem	Language	Result	Execution time	Memory
630925		garam1732	Thousands Islands (IOI22_islands)	C++17	0 / 100	70 ms	10332 KiB

islands

#include "islands.h"

#include <iostream>
#include <variant>
#include <vector>
#include <algorithm>
#include <map>
#define ff first
#define ss second
using namespace std;
typedef pair<int, int> pi;

map<pi, int> m;
vector<pi> adj[100100];
vector<pi> v;
vector<int> ans;
bool visited[100100];
int x = -1;

void dfs(int here) {
    visited[here] = true;

    //cout << here << endl;
    for(pi there : adj[here]) {
        if(visited[there.ff]) {
            v.push_back(there);
            x = there.ff;
            return;
        }

        v.push_back(there);
        dfs(there.ff);
        if(x != -1) return;
        v.pop_back();
    }
}

vector<int> em;
//vector<int> find_journey(
std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {
    for(int i = 0; i < M; i+=2) {
        if(m.find(pi(U[i], V[i])) == m.end()) {
        adj[U[i]].push_back(pi(V[i], i));
        }
        //adj[V[i]].push_back(pi(U[i], i));
        m[pi(U[i], V[i])] = 1;
    }

    dfs(0);

    if(x == -1) return false;

    int i;
    for(i = 0; i < v.size(); i++) if(v[i].ff == x) break;

    if(i == (int)v.size()-1) i = -1;
    for(int j = 0; j <= i; j++) ans.push_back(v[j].ss);
    for(int j = i+1; j < v.size(); j++) ans.push_back(v[j].ss);
    for(int j = i+1; j < v.size(); j++) ans.push_back(v[j].ss^1);
    for(int j = (int)v.size()-1; j > i; j--) ans.push_back(v[j].ss);
    for(int j = (int)v.size()-1; j > i; j--) ans.push_back(v[j].ss^1);
    for(int j = i; j >= 0; j--) ans.push_back(v[j].ss);
    return ans;

//    std::vector<int> v, w;
//    for(int i = 0; i < M; i++) {
//        if(U[i] == 0) v.push_back(i);
//        else w.push_back(i);
//    }
//
//    if(v.size() < 2 || w.size() < 1) {
//        return em;
//        //return false;
//    }
//    std::vector<int> ans;
//    ans.push_back(v[0]);
//    ans.push_back(w[0]);
//    ans.push_back(v[1]);
//    ans.push_back(v[0]);
//    ans.push_back(w[0]);
//    ans.push_back(v[1]);
//    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:55:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |     for(i = 0; i < v.size(); i++) if(v[i].ff == x) break;
      |                ~~^~~~~~~~~~
islands.cpp:59:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |     for(int j = i+1; j < v.size(); j++) ans.push_back(v[j].ss);
      |                      ~~^~~~~~~~~~
islands.cpp:60:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for(int j = i+1; j < v.size(); j++) ans.push_back(v[j].ss^1);
      |                      ~~^~~~~~~~~~

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