Submission #893094

#	Time	Username	Problem	Language	Result	Execution time	Memory
893094		raul2008487	Dreaming (IOI13_dreaming)	C++17	18 / 100	54 ms	15312 KiB

dreaming

#include<bits/stdc++.h>
#include "dreaming.h"
#define ll long long
#define pll pair<ll,ll>
#define vl vector<ll>
#define fi first
#define se second
#define in insert
#define all(v) v.begin(),v.end()
const int sz = 100005;
const ll inf = 1000000000000000;
using namespace std;
vector<pair<ll,ll>> adj[sz];
ll dis[sz][2], center, v1, v2, mx, cnt = -1;
bool used[sz];
vector<vector<ll>> path;
void trav(ll node){
    used[node] = 1;
    path[cnt].push_back(node);
    for(pll edge: adj[node]){
        if(!used[edge.fi]){
            trav(edge.fi);
        }
    }
}
void dfs(ll node, ll we, ll p){
    if(we > mx){
        v2 = node;
        mx = we;
    }
    for(pll edge: adj[node]){
        if(edge.fi != p){
            dfs(edge.fi, we + edge.se, node);
        }
    }
}
void caldis(ll node, ll we, ll p, ll type){
    dis[node][type] = we;
    for(pll edge: adj[node]){
        if(edge.fi != p){
            caldis(edge.fi, we + edge.se, node, type);
        }
    }
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    ll n = N, m = M, i, j, ans = 0;
    for(i=1;i<=m;i++){
        adj[A[i]].push_back({B[i], T[i]});
        adj[B[i]].push_back({A[i], T[i]});
    }
    for(i=0;i<n;i++){
        if(!used[i]){
            cnt++;
            path.push_back(vl(0));
            trav(i);
        }
    }
    array<ll, 3> bp = {-1, -1, -1};
    ll worst = inf;
    for(i=0;i<=cnt;i++){
        mx = -1, v1 = -1, v2 = -1;
        dfs(path[i][0], 0, -1);
        v1 = v2;
        mx = -1;
        dfs(v1, 0, -1);
        caldis(v1, 0, -1, 0);caldis(v2, 0, -1, 1);
        ans = max(ans, mx);
        ll pc = path[i][0], pb = max(dis[pc][0], dis[pc][1]);
        for(auto x: path[i]){
            if(max(dis[x][0], dis[x][1]) < pb){
                pb = max(dis[x][0], dis[x][1]);
            }
        }
        worst = min(worst, pb);
        //ans = max(ans, pb);
        if(pb > bp[0]){
            bp[2] = bp[1];
            bp[1] = bp[0];
            bp[0] = pb;
        }
        else if(pb > bp[1]){
            bp[2] = bp[1];
            bp[1] = pb;
        }
        else if(pb > bp[2]){
            bp[2] = pb;
        }
    }
    if(cnt == 0){
      return ans;
    }
    ans = max(ans, bp[0] + bp[1] + L);
    if(bp[2] != -1){
        ans = max(ans, bp[1] + bp[2] + 2*L);
    }
    return ans;
 
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:46:25: warning: unused variable 'j' [-Wunused-variable]
   46 |     ll n = N, m = M, i, j, ans = 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