Submission #272901

#	Time	Username	Problem	Language	Result	Execution time	Memory
272901		MarcoMeijer	Potemkin cycle (CEOI15_indcyc)	C++14	70 / 100	1096 ms	57464 KiB

indcyc

#include <bits/stdc++.h>
using namespace std;

// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e9
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }

// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }

//===================//
//  Added libraries  //
//===================//

//===================//
//end added libraries//
//===================//

void program();
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    program();
}


//===================//
//   begin program   //
//===================//

const int MX = 5e5;

int n, m;
int a[MX], b[MX];
set<int> adj[MX];
bitset<MX> used;

int p[MX], r[MX];
set<int> adjG[MX];
stack<iii> stck;
void buildDSU(int dsuSize) {
    RE(i,dsuSize) p[i]=i, r[i]=0, adjG[i].clear();
    while(!stck.empty()) stck.pop();
}
int getSet(int i) {return i==p[i]?i:getSet(p[i]);}
bool isSameSet(int i, int j) {return getSet(i)==getSet(j);}
void unionSet(int i, int j) {
    i=getSet(i), j=getSet(j);
    if(r[i] > r[j]) {
        stck.push({j,i,r[i]});
        p[j] = i;
    } else {
        p[i] = j;
        stck.push({i,j,r[j]});
        if(r[i] == r[j] && i != j) r[j]++;
    }
}
void unionUndo() {
    int i, j, rj;
    tie(i,j,rj) = stck.top(); stck.pop();
    r[j] = rj;
    p[i] = i;
}

vi ans;
int par[MX];
bitset<MX> visited;
void findShortestPath(int x, int y) {
    visited.reset(); visited[x] = 1;
    queue<int> q; q.push(x);
    while(!q.empty()) {
        int u = q.front(); q.pop();
        FOR(v,adj[u]) if(!visited[v]) {
            visited[v] = 1;
            q.push(v);
            par[v] = u;
        }
    }
    while(y != x) {
        ans.pb(y);
        y = par[y];
    }
    ans.pb(x);
}

void program() {
    IN(n,m);
    RE(i,m) {
        int u, v; IN(u, v);
        adj[u].insert(v);
        adj[v].insert(u);
        a[i] = u; b[i] = v;
    }
    RE1(u,n) {
        // create initial dsu
        used.reset();
        buildDSU(n+1);
        used[u] = 1;
        FOR(v,adj[u]) used[v] = 1;
        RE(i,m) {
            int u=a[i], v=b[i];
            if(used[u] || used[v]) continue;
            unionSet(u, v);
        }

        RE1(i,n) {
            if(used[i]) continue;
            FOR(v,adj[i]) {
                if(!used[v] || v == u) continue;
                adjG[getSet(i)].insert(v);
            }
        }
        RE1(i,n)
        FOR(x,adjG[i]) {
            FOR(y,adjG[i]) {
                if(adj[x].count(y) || x == y) continue;

                // found answer
                used[x] = 0;
                used[y] = 0;
                RE1(i,n) adj[i].clear();
                RE(i,m) {
                    int u=a[i], v=b[i];
                    if(used[u] || used[v]) continue;
                    adj[u].insert(v);
                    adj[v].insert(u);
                }
                ans.pb(u);
                findShortestPath(x,y);
                RE(i,ans.sz) OUT(i==0?"":" ", ans[i]); OUTL();
                return;
            }
        }
    }
    OUTL("no");
}

Compilation message (stderr)

indcyc.cpp: In function 'void program()':
indcyc.cpp:15:20: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   15 | #define REP(a,b,c) for(int a=int(b); a<int(c); a++)
      |                    ^~~
indcyc.cpp:16:17: note: in expansion of macro 'REP'
   16 | #define RE(a,c) REP(a,0,c)
      |                 ^~~
indcyc.cpp:164:17: note: in expansion of macro 'RE'
  164 |                 RE(i,ans.sz) OUT(i==0?"":" ", ans[i]); OUTL();
      |                 ^~
indcyc.cpp:164:56: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  164 |                 RE(i,ans.sz) OUT(i==0?"":" ", ans[i]); OUTL();
      |                                                        ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10