Submission #575680

#	Time	Username	Problem	Language	Result	Execution time	Memory
575680		enerelt14	Dreaming (IOI13_dreaming)	C++14	100 / 100	98 ms	19792 KiB

dreaming

#include "dreaming.h"
#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
using namespace std;
//int N, M, L, A[100005], B[100005], T[100005];
int p[100005], d[100005], ans=0;
int find(int s){
    if (s==p[s])return s;
    return p[s]=find(p[s]);
}
void Union_find(int x, int y){
    int z=find(x), t=find(y);
    p[max(z, t)]=min(z, t);
}
vector<pair<int, int> >adj[100005];
vector<int>x[100005];
vector<int>y;
int mx_d[100005]={0}, sec[100005]={0};
bool is[100005]={0};
void dfs(int u, int par){
    p[u]=par;
    for (int i=0;i<adj[u].size();i++){
        int v=adj[u][i].ff;
        if (v==par)continue;
        dfs(v, u);
        if (mx_d[u]<mx_d[v]+adj[u][i].ss){
            mx_d[u]=mx_d[v]+adj[u][i].ss;
            is[u]=0;
            continue;
        }
        if (mx_d[u]==mx_d[v]+adj[u][i].ss){
            is[u]=1;
        }
    }
    if (is[u])sec[u]=mx_d[u];
    for (int i=0;i<adj[u].size();i++){
        int v=adj[u][i].ff;
        if (v!=par && mx_d[u]!=mx_d[v]+adj[u][i].ss)sec[u]=max(sec[u], mx_d[v]+adj[u][i].ss);
    }
    ans=max(ans, mx_d[u]+sec[u]);
}
void solve(int s, int u, int dis){
    d[s]=min(d[s], max(dis, mx_d[u]));
    for (int i=0;i<adj[u].size();i++){
        int v=adj[u][i].ff;
        if (v==p[u])continue;
        if (mx_d[v]+adj[u][i].ss==mx_d[u])solve(s, v, max(dis, sec[u])+adj[u][i].ss);
        else solve(s, v, max(dis, mx_d[u])+adj[u][i].ss);
    }
}
int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    memset(mx_d, 0, sizeof(mx_d));
    if (N==1)return 0;
    if (N==2){
        if (M==1)return T[0];
        else return L;
    }
    for (int i=0;i<N;i++)p[i]=i;
    for (int i=0;i<M;i++){
        Union_find(A[i], B[i]);
        adj[A[i]].pb(mp(B[i], T[i]));
        adj[B[i]].pb(mp(A[i], T[i]));
    }
    for (int i=0;i<N;i++){
        x[find(i)].pb(i);
    }
    for (int i=0;i<N;i++){
        if (x[i].empty())continue;
        y=x[i];
        dfs(y[0], y[0]);
        d[i]=mx_d[y[0]];
        for (int j=0;j<adj[y[0]].size();j++){
            if (mx_d[adj[y[0]][j].ff]+adj[y[0]][j].ss==mx_d[y[0]]){
                solve(i, adj[y[0]][j].ff, sec[y[0]]+adj[y[0]][j].ss);
            }
            else solve(i, adj[y[0]][j].ff, mx_d[y[0]]+adj[y[0]][j].ss);
        }
    }
    sort(d, d+N);
    if (M==N-1)return ans;
    if (M==N-2)return max(ans, d[N-1]+d[N-2]+L);
    return max(ans, max(d[N-1]+d[N-2]+L, d[N-2]+d[N-3]+2*L));
}

Compilation message (stderr)

dreaming.cpp: In function 'void dfs(int, int)':
dreaming.cpp:25:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |     for (int i=0;i<adj[u].size();i++){
      |                  ~^~~~~~~~~~~~~~
dreaming.cpp:39:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     for (int i=0;i<adj[u].size();i++){
      |                  ~^~~~~~~~~~~~~~
dreaming.cpp: In function 'void solve(int, int, int)':
dreaming.cpp:47:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |     for (int i=0;i<adj[u].size();i++){
      |                  ~^~~~~~~~~~~~~~
dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:75:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |         for (int j=0;j<adj[y[0]].size();j++){
      |                      ~^~~~~~~~~~~~~~~~~

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