Submission #469120

#	Time	Username	Problem	Language	Result	Execution time	Memory
469120		kevinxiehk	Keys (IOI21_keys)	C++17	9 / 100	357 ms	91488 KiB

keys

#include <bits/stdc++.h>
#define mp make_pair
#define pb emplace_back
#define fi first
#define se second
using namespace std;
set<int> conn[300005];
set<int> conn2[300005];
stack<int> rec;
pair<int, int> val[300005];
bool instack[300005];
int scc[300005];
int sz[300005];
vector<int> component[300005];
int cnt = 0;
int n, m, t, tt, k = 1;
void dfs(int now) {
    val[now] = mp(k, k);
    k++;
    rec.push(now);
    instack[now] = true;
    for(auto x: conn[now]) {
        if(val[x].fi == 0) {
            dfs(x);
        }
        if(instack[x]) {
            val[now].se = min(val[now].se, val[x].se);
        }
    }
    if(val[now].se == val[now].fi) {
        cnt++;
        while(rec.top() != now) {
            instack[rec.top()] = false;
            scc[rec.top()] = cnt;
            component[cnt].pb(rec.top());
            rec.pop();
        }
        instack[rec.top()] = false;
        scc[rec.top()] = cnt;
        component[cnt].pb(rec.top());
        rec.pop();
    }
}
vector<int> find_reachable(vector<int> r, vector<int> u, vector<int> v, vector<int> c) {
    n = r.size();
    m = u.size();
    for(int i = 0; i < m; i++) {
        if(r[u[i]] == c[i]) conn[u[i]].insert(v[i]);
        if(r[v[i]] == c[i]) conn[v[i]].insert(u[i]);
    }
    for(int i = 0; i < n; i++) if(val[i].fi == 0) dfs(i);
    for(int i = 0; i < n; i++) {
        for(auto x: conn[i]) {
            if(scc[i] != scc[x]) conn2[scc[i]].insert(scc[x]);
        }
    }
    int mi = n + 5;
    for(int i = 1; i <= cnt; i++) if(conn2[i].size() == 0) mi = min(mi, (int)(component[i].size()));
	vector<int> ans(r.size(), 0);
    for(int i = 1; i <= cnt; i++) {
        if(conn2[i].size() == 0 && component[i].size() == mi) {
            for(auto x: component[i]) ans[x] = true;
        }
    }
	return ans;
}

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:61:56: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   61 |         if(conn2[i].size() == 0 && component[i].size() == mi) {
      |                                    ~~~~~~~~~~~~~~~~~~~~^~~~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 11
• Subtask 3: 0 / 17
• Subtask 4: 0 / 30
• Subtask 5: 0 / 33