제출 #1010531

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1010531		GrindMachine	수천개의 섬 (IOI22_islands)	C++17	9.10 / 100	56 ms	16208 KiB

islands

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

#include "islands.h"

set<int> adj[N];
vector<bool> vis(N), recstack(N);
bool cyc = false;

void dfs1(int u){
    vis[u] = 1;
    recstack[u] = 1;

    trav(v,adj[u]){
        if(vis[v]){
            if(recstack[v]){
                cyc = true;
            }
        }
        else{
            dfs1(v);
        }
    }

    recstack[u] = 0;
}

bool line = true;

void dfs2(int u, int p){
    vis[u] = 1;
    if(sz(adj[u]) > 2){
        line = false;
    }

    trav(v,adj[u]){
        if(v == p or vis[v]) conts;
        dfs2(v,u);
    }
}

struct DSU {
    vector<int> par, rankk, siz;
    vector<int> bad;

    DSU() {

    }

    DSU(int n) {
        init(n);
    }

    void init(int n) {
        par = vector<int>(n + 1);
        rankk = vector<int>(n + 1);
        siz = vector<int>(n + 1);
        bad = vector<int>(n + 1);
        rep(i, n + 1) create(i);
    }

    void create(int u) {
        par[u] = u;
        rankk[u] = 0;
        siz[u] = 1;
    }

    int find(int u) {
        if (u == par[u]) return u;
        else return par[u] = find(par[u]);
    }

    bool same(int u, int v) {
        return find(u) == find(v);
    }

    void merge(int u, int v) {
        u = find(u), v = find(v);
        if (u == v){
            bad[u] = 1;
            return;
        }

        if (rankk[u] == rankk[v]) rankk[u]++;
        if (rankk[u] < rankk[v]) swap(u, v);

        par[v] = u;
        siz[u] += siz[v];
        bad[u] |= bad[v];
    }
};

std::variant<bool, std::vector<int>> find_journey(
    int n, int m, std::vector<int> U, std::vector<int> V) {

    DSU dsu(n);

    for(int i = 0; i < m; i += 2){
        int u = U[i], v = V[i];
        adj[u].insert(v), adj[v].insert(u);
        dsu.merge(u,v);
    }

    dfs2(0,-1);

    int p = dsu.find(0);
    bool ans = dsu.bad[p];
    if(!line) ans = 1;

    return ans;

    // if (n == 4) {
    //     return std::vector<int>({0, 1, 2, 4, 0, 3, 2, 1, 4, 3});
    // }

    // return false;
}

• Subtask 1: 0 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 7.35 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45