Submission #823733

#	Time	Username	Problem	Language	Result	Execution time	Memory
823733		becaido	Keys (IOI21_keys)	C++17	100 / 100	1742 ms	67588 KiB

keys

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifndef WAIMAI
#include "keys.h"
#endif

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

const int SIZE = 3e5 + 5;

int n;
int r[SIZE], a[SIZE];
vector<pair<int, int>> adj[SIZE];

int to[SIZE];
int dsu(int x) {
    return x == to[x] ? x : (to[x] = dsu(to[x]));
}

vector<int> deal(int s, bool is = 0) {
    unordered_set<int> us, vs;
    unordered_map<int, vector<int>> mp;
    queue<int> q;
    q.push(s);
    vs.insert(s);
    while (q.size()) {
        int pos = q.front();
        q.pop();
        if (!us.count(r[pos])) {
            us.insert(r[pos]);
            for (int x : mp[r[pos]]) {
                if (dsu(x) != s) return vector<int>(1, dsu(x));
                q.push(x);
                vs.insert(x);
            }
            mp[r[pos]].clear();
        }
        for (auto [np, c] : adj[pos]) if (!vs.count(np)) {
            if (us.count(c)) {
                if (dsu(np) != s) return vector<int>(1, dsu(np));
                q.push(np);
                vs.insert(np);
            } else {
                mp[c].emplace_back(np);
            }
        }
    }
    if (!is) return vector<int>(1, -1);
    vector<int> all;
    for (int x : vs) all.pb(x);
    return all;
}

vector<int> find_reachable(vector<int> _r, vector<int> u, vector<int> v, vector<int> c) {
    n = _r.size();
    FOR (i, 0, n - 1) {
        r[i] = _r[i];
        to[i] = i;
    }
    FOR (i, 0, u.size() - 1) {
        adj[u[i]].pb(v[i], c[i]);
        adj[v[i]].pb(u[i], c[i]);
    }
    while (true) {
        FOR (i, 0, n - 1) if (dsu(i) == i) a[i] = deal(i)[0];
        bool f = 0;
        FOR (i, 0, n - 1) if (dsu(i) == i && a[i] != -1) {
            to[i] = dsu(a[i]);
            f = 1;
        }
        if (!f) break;
    }
    int mn = n + 1;
    vector<int> ansp, ans(n);
    FOR (i, 0, n - 1) if (dsu(i) == i) {
        auto v = deal(i, 1);
        if (v.size() < mn) {
            mn = v.size();
            ansp.clear();
        }
        if (v.size() == mn) ansp.insert(ansp.end(), v.begin(), v.end());
    }
    for (int x : ansp) ans[x] = 1;
    return ans;
}

#ifdef WAIMAI
int main() {
    int n, m;
    assert(2 == scanf("%d%d", &n, &m));
    vector<int> r(n), u(m), v(m), c(m);
    for(int i=0; i<n; i++) {
        assert(1 == scanf("%d", &r[i]));
    }
    for(int i=0; i<m; i++) {
        assert(3 == scanf("%d %d %d", &u[i], &v[i], &c[i]));
    }

    vector<int> ans = find_reachable(r, u, v, c);

    for (int i = 0; i < (int) ans.size(); ++i) {
        if(i) putchar(' ');
        putchar(ans[i]+'0');
    }
    printf("\n");
    return 0;
}
#endif

Compilation message (stderr)

keys.cpp: In function 'std::vector<int> find_reachable(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
keys.cpp:94:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   94 |         if (v.size() < mn) {
      |             ~~~~~~~~~^~~~
keys.cpp:98:22: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   98 |         if (v.size() == mn) ansp.insert(ansp.end(), v.begin(), v.end());
      |             ~~~~~~~~~^~~~~

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 30 / 30
• Subtask 5: 33 / 33