Submission #660991

#	Time	Username	Problem	Language	Result	Execution time	Memory
660991		urosk	Toy Train (IOI17_train)	C++14	22 / 100	1674 ms	1404 KiB

train

#include "train.h"
#define dbg(x) cerr<<#x<<": "<<x<<endl
#define here cerr<<"===================================\n"
#include <bits/stdc++.h>
#define ll int
#define sz(a) (ll)(a.size())
#define pb push_back
#define popb pop_back
#define all(a) a.begin(),a.end()
#define llinf 1000000000LL
#define fi first
#define sc second
#define pll pair<ll,ll>
#define endl '\n'
#define ceri(a,l,r) {cerr<<#a<<": ";for(ll i_ = l;i_<=r;i_++) cerr<<a[i_]<< " ";cerr<<endl;}
using namespace std;
#define maxn 5005
ll n,m,it;
vector<ll> ans;
vector<ll> g[maxn];
vector<ll> cur;
ll b[maxn];
bool c[maxn];
bool vis[maxn];
bool naso = 0;
bool ok[maxn];
ll cnt = 0;
ll in[maxn],out[maxn];
void dfs(ll u,ll poc){
    vis[u] = 1;
    for(ll s : g[u]){
        if(c[s]) continue;
        if(s==poc){
            naso = 1;
            return;
        }
        if(vis[s]) continue;
        dfs(s,poc);
        if(naso) return;
    }
}
void dfs2(ll u,ll poc){
    if(c[u]) cnt++;
    vis[u] = 1;
    for(ll s : g[u]){
        if((s==poc)&&(cnt>0)){
            naso = 1;
            return;
        }
        if(vis[s]) continue;
        dfs2(s,poc);
        if(naso) return;
    }
    if(c[u]) cnt--;
}
void dfs3(ll u){
    vis[u] = 1;
    for(ll s : g[u]){
        if(vis[s]) continue;
        dfs3(s);
        ok[u]|=ok[s];
    }
}
bool dfs4(ll u){
    bool tu = 0;
    for(ll s : g[u]) if(s==u) tu = 1;
    if(!tu){
        if(sz(g[u])==0){
            cout<<u<<endl;
            return 1;
        }
        return dfs4(g[u][0]);
    }
    if(!b[u]&&!c[u]) return 0;
    if(b[u]&&c[u]) return 1;
    for(ll s : g[u]){
        if(s!=u) return dfs4(s);
    }
}
vector<int> who_wins(vector<int> a,vector<int> r,vector<int> u,vector<int> v) {
    reverse(all(u)); u.pb(-1); reverse(all(u));
    reverse(all(v)); v.pb(-1); reverse(all(v));
    reverse(all(r)); r.pb(-1); reverse(all(r));
    ll sum = 0; for(ll x : a) sum+=x;
    n = sz(a);
    reverse(all(a)); a.pb(-1); reverse(all(a));
    for(ll i = 1;i<=n;i++) b[i] = a[i];
    m = sz(u)-1;
    bool sub1 = 1;
    for(ll i = 1;i<=n;i++) c[i] = r[i];
    for(ll i = 1;i<=m;i++){
        u[i]++; v[i]++;
        ll x = u[i]; ll y = v[i];
        g[x].pb(y);
        sub1&=((x==y)||(y-x==1));
    }
    if(sum==0){
        for(ll i = 1;i<=n;i++){
            if(c[i]) continue;
            for(ll j = 1;j<=n;j++) vis[j] = 0;
            naso = 0;
            dfs(i,i);
            if(naso) ok[i] = 1;
        }
        for(ll i = 1;i<=n;i++){
            for(ll j = 1;j<=n;j++) vis[j] = 0;
            dfs3(i);
        }
        for(ll i = 1;i<=n;i++) ans.pb(1^ok[i]);
        return ans;
    }
    if(sum==n){
        for(ll i = 1;i<=n;i++){
            for(ll j = 1;j<=n;j++) vis[j] = 0;
            naso = 0;
            cnt = 0;
            dfs2(i,i);
            if(naso) ok[i] = 1;
        }
        for(ll i = 1;i<=n;i++){
            for(ll j = 1;j<=n;j++) vis[j] = 0;
            dfs3(i);
        }
        for(ll i = 1;i<=n;i++) ans.pb(ok[i]);
        return ans;
    }
    if(sub1){
        for(ll i = 1;i<=n;i++){
            for(ll j = 1;j<=n;j++) vis[j] = 0;
            ok[i] = dfs4(i);
        }
        for(ll i = 1;i<=n;i++) ans.pb(ok[i]);
        return ans;
    }
	return {};
}

/*
4 6
0 0 0 0
0 1 0 0
0 1
0 2
0 3
1 2
1 3
2 3
*/

Compilation message (stderr)

train.cpp: In function 'bool dfs4(int)':
train.cpp:79:1: warning: control reaches end of non-void function [-Wreturn-type]
   79 | }
      | ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 11 / 11
• Subtask 4: 11 / 11
• Subtask 5: 0 / 12
• Subtask 6: 0 / 51