Submission #116714

#	Time	Username	Problem	Language	Result	Execution time	Memory
116714		JohnTitor	Pipes (CEOI15_pipes)	C++11	100 / 100	719 ms	15404 KiB

pipes

#include <vector>
#include <algorithm>
#include <stdio.h>
#include <locale>
using namespace std;
#define FOR(i, j, k) for(int i=(j); i<=(k); i++)
#define FFOR(i, j, k) for(int i=(j); i<(k); i++)
#define DFOR(i, j, k) for(int i=(j); i>=(k); i--)
#define bug(x) cerr<<#x<<" = "<<(x)<<'\n'
#define pb push_back
#define mp make_pair
#define bit(s, i) (((s)>>(i))&1LL)
#define mask(i) ((1LL<<(i)))
#define builtin_popcount __builtin_popcountll
#define __builtin_popcount __builtin_popcountll
using ll=long long; using ld=long double;
//mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count()); const ld pi=acos(0)*2;
template <typename T> inline void read(T &x){char c; bool nega=0; while((!isdigit(c=getchar()))&&(c!='-')); if(c=='-'){nega=1; c=getchar();} x=c-48; while(isdigit(c=getchar())) x=x*10+c-48; if(nega) x=-x;}
template <typename T> inline void writep(T x){if(x>9) writep(x/10); putchar(x%10+48);}
template <typename T> inline void write(T x){if(x<0){ putchar('-'); x=-x;} writep(x);}
template <typename T> inline void writeln(T x){write(x); putchar('\n');}
#define taskname "Pipes"
class dsu{
public:
    int n;
    vector <int> r;
    vector <pair <int, int>> edges;
    void reset(int n){
        this->n=n;
        r.resize(n+1);
        FOR(i, 1, n) r[i]=-1;
        edges.clear();
    }
    int root(int u){
        if(r[u]<0) return u;
        return r[u]=root(r[u]);
    }
    bool unite(int u, int v){
        int ou=u;
        int ov=v;
        u=root(u);
        v=root(v);
        if(u==v) return 0;
        edges.pb(mp(ou, ov));
        if(r[u]>r[v]) swap(u, v);
        r[u]+=r[v];
        r[v]=u;
        return 1;
    }
} d[2];
int n, m;
vector <int> g[100001];
vector <bool> done;
int cnt=0;
vector <int> low;
vector <int> num;
vector <int> p;
void dfs(int u){
    done[u]=1;
    cnt++;
    num[u]=low[u]=cnt;
    for(auto &x: g[u]) if(x==p[u]){
        swap(x, g[u].back());
        g[u].pop_back();
        break;
    }
    for(int &v: g[u]) if(!done[v]){
        p[v]=u;
        dfs(v);
        low[u]=min(low[u], low[v]);
    }
    else low[u]=min(low[u], num[v]);
    for(int &v: g[u]) if(p[v]==u){
        if(low[v]>num[u]){
            write(u);
            putchar(' ');
            writeln(v);
        }
        p[v]=0;
    }
}
int main(){
    #ifdef Aria
        if(fopen(taskname".in", "r"))
            freopen(taskname".in", "r", stdin);
    #endif // Aria
    read(n);
    read(m);
    d[0].reset(n);
    d[1].reset(n);
    {
        int u, v;
        FOR(i, 1, m){
            read(u);
            read(v);
            if(!d[0].unite(u, v)) d[1].unite(u, v);
        }
    }
    FOR(b, 0, 1){
        while(!d[b].edges.empty()){
            auto p=d[b].edges.back();
            d[b].edges.pop_back();
            g[p.first].pb(p.second);
            g[p.second].pb(p.first);
        }
        d[b].r.clear();
    }
    done.resize(n+1, 0);
    num.resize(n+1, 0);
    low.resize(n+1, 0);
    p.resize(n+1, 0);
    FOR(i, 1, n) if(!done[i]) dfs(i);
}

• 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: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10