Submission #218071

#	Time	Username	Problem	Language	Result	Execution time	Memory
218071		summitwei	Dreaming (IOI13_dreaming)	C++17	18 / 100	71 ms	16116 KiB

dreaming

#include <bits/stdc++.h>
#include <dreaming.h>
using namespace std;
typedef vector<int> vi;
typedef vector<pair<int, int> > vpii;
typedef pair<int, int> pii;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;
typedef vector<ll> vll;
#define INF 0x3f3f3f3f
#define MOD 1000000007LL
#define EPSILON 0.00001
#define f first
#define s second
#define pb push_back
#define mp make_pair

#define FOR(i, a, b) for (ll i=(a); i<=(signed)(b); i++)
#define F0R(i, a) for (ll i=0; i<(signed)(a); i++)
#define RFOR(i, a, b) for (ll i=(a); i >= b; i--)

#define MN 100005
vpii e[MN];
int vis[MN];
pii far(int cn, int p){ //{dist, node}
    vis[cn] = true;
    pii ans = {0, cn};
    for(auto nn : e[cn]) if(nn.f != p){
        pii res = far(nn.f, cn);
        ans = max(ans, {res.f+nn.s, res.s});
    }
    return ans;
}
int d[2][MN];
int cmn;
void gda(int t, int cn, int p){
    if(t == 1){
        cmn = min(cmn, max(d[0][cn], d[1][cn]));
    }
    for(auto nn : e[cn]) if(nn.f != p){
        d[t][nn.f] = d[t][cn]+nn.s;
        gda(t, nn.f, cn);
    }
}
int diam(int x){
    pii res1 = far(x, 0);
    pii res2 = far(res1.s, 0);
    //return {res2.f, {res1.s, res2.s}};
    cmn = INF;
    gda(0, res1.s, 0);
    gda(1, res2.s, 0);
    return cmn;
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
    int n = N; int m = M; int l = L;
    F0R(i, m){
        e[A[i]].pb({B[i], T[i]});
        e[B[i]].pb({A[i], T[i]});
    }
    vi hmm;
    F0R(i, n){
        if(!vis[i]){
            hmm.pb(diam(i));
        }
    }
    sort(hmm.begin(), hmm.end(), greater<int>() );
    if(hmm.size() == 1){
        return hmm[0];
    } else if(hmm.size() == 2){
        return hmm[0]+hmm[1]+l;
    } else{
        return max(hmm[0]+hmm[1]+l, hmm[1]+hmm[2]+l+l);
    }
}

/*int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int N, M, L;
    cin >> N >> M >> L;
    int A[M], B[M], T[M];
    F0R(i, M) cin >> A[i] >> B[i] >> T[i];

    cout << travelTime(N, M, L, A, B, T) << "\n";
    
    return 0;
}*/

• Subtask 1: 0 / 14
• Subtask 2: 0 / 10
• Subtask 3: 0 / 23
• Subtask 4: 18 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23