Submission #337329

#	Time	Username	Problem	Language	Result	Execution time	Memory
337329		bigDuck	Dreaming (IOI13_dreaming)	C++14	100 / 100	136 ms	24812 KiB

dreaming

#include "dreaming.h"
#include<bits/stdc++.h>
using namespace std;
#define INIT  ios_base :: sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define mp make_pair
#define pb push_back
#define ft first
#define sc second
#define ll long long
#define pii pair<int, int>
#define count_bits __builtin_popcount
#define int ll




vector<pii> g[100010];
int dp[100010][2];
pii dir[100010][2];



bool v[100010];

int h[100010], c;
int d[100010];


int dfs(int s){
v[s]=true;

for(pii e:g[s]){
    int l=e.sc, u=e.ft;
    if(!v[u]){
        dfs(u);
        if( (dp[u][0]+l)>dp[s][0]){
            dp[s][1]=dp[s][0];
            dp[s][0]=dp[u][0]+l;

            dir[s][1]=dir[s][0];
            dir[s][0]={u, l};
        }
        else{
            if( (dp[u][0]+l)>dp[s][1] ){
                dp[s][1]=dp[u][0]+l;
                dir[s][1]={u, l};
            }
        }
    }

}


return dp[s][0];
}




int dfs2(int s, int up){
int ac=dp[s][0];

if(ac<=up ){
    return ac;
}
int l=dir[s][0].sc;
int r=dfs2(dir[s][0].ft, max(up+l, dp[s][1]+l) );


if( ( max(r , max(up+l, dp[s][1]+l) )<max(up, dp[s][0])  )   ){
    return max(r, max(up+l, dp[s][1]+l));
}
else{
    return max(up, dp[s][0]);
}

}



bool v2[100010];

pii diam(int s){
    v2[s]=true;

    pii r={0, s};
    for(pii e:g[s]){
        int u=e.ft, l=e.sc;
        if(!v2[u]){
            pii p=diam(u); p.ft+=l;
            if(p.ft>=r.ft){
                r=p;
            }
        }
    }
    v2[s]=false;
    return r;
}







int32_t travelTime(int32_t n, int32_t m, int32_t l, int32_t a[], int32_t b[], int32_t t[]){

    for(int i=0;i<m; i++){
        int u=a[i], v=b[i];
        g[u].pb({v, t[i]}); g[v].pb({u, t[i]});
    }
    int res=0;
    for(int i=0; i<n; i++){
        if(!v[i]){
            c++;
            dfs(i);
            int r=dfs2(i, dp[i][1]);
            pii p=diam(i);
            p=diam(p.sc);
            d[c]=p.ft;
            h[c]=r;
            res=max(res, d[c]);
        }
    }

    sort(h+1, h+1+c);
    if(c>=2){
        res=max(res, l+h[c]+h[c-1]);
    }
    if(c>2){
        res=max(res, l*2+h[c-1]+h[c-2]);
    }

    return res;
}

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