Submission #735124

#	Time	Username	Problem	Language	Result	Execution time	Memory
735124		sandry24	Dreaming (IOI13_dreaming)	C++17	32 / 100	68 ms	15196 KiB

dreaming

#include <bits/stdc++.h>
#include "dreaming.h"
using namespace std;
 
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define pb push_back
#define mp make_pair
#define f first
#define s second
 
vector<vector<pi>> adj(1e5+1);
vector<bool> visited(1e5+1);
vi parent(1e5+1), dists(1e5+1);
 
ll maxe = -1, maxnode = -1;
 
void dfs(ll x, ll p=-1, ll dist=0){
    visited[x] = 1;
    parent[x] = p;
    dists[x] = dist;
    if(dist > maxe){
        maxe = dist;
        maxnode = x;
    }
    for(auto i : adj[x]){
        if(i.f != p)
            dfs(i.f, x, dist + i.s);
    }
}
 
int travelTime(int N, int M, int L, int A[], int B[], int T[]){
    for(int i = 0; i < M; i++){
        adj[A[i]].pb({B[i], T[i]});
        adj[B[i]].pb({A[i], T[i]});
    }
    vector<pair<ll, ll>> centers;
    for(int i = 0; i < N; i++){
        if(!visited[i]){
            maxe = -1, maxnode = -1;
            dfs(i);
            ll n1 = maxnode;
            maxe = -1, maxnode = -1;
            dfs(n1);
            ll n2 = maxnode;
            vector<pair<ll, ll>> path;
            while(n2 != n1){
                path.pb({n2, dists[n2]});
                n2 = parent[n2];
            }
            path.pb({n2, dists[n2]});
            reverse(path.begin(), path.end());
            ll diameter = path.back().second;
            ll best_node = -1, best_dist = 1e18;
            for(int j = 0; j < path.size(); j++){
                if(max(path[j].s, diameter - path[j].s) < best_dist){
                    best_node = path[j].f;
                    best_dist = max(path[j].s, diameter - path[j].s);
                }
            }
            centers.pb({best_dist, best_node});
        }
    }
    sort(centers.begin(), centers.end(), greater<pair<ll, ll>>());
    for(int i = 1; i < centers.size(); i++){
        adj[centers[0].s].pb({centers[i].s, L});
        adj[centers[i].s].pb({centers[0].s, L});
    }
    dfs(0);
    maxe = -1;
    dfs(maxnode);
    return dists[maxnode];
}

Compilation message (stderr)

dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:58:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |             for(int j = 0; j < path.size(); j++){
      |                            ~~^~~~~~~~~~~~~
dreaming.cpp:68:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |     for(int i = 1; i < centers.size(); i++){
      |                    ~~^~~~~~~~~~~~~~~~

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