Submission #157543

#	Time	Username	Problem	Language	Result	Execution time	Memory
157543		GioChkhaidze	Dreaming (IOI13_dreaming)	C++14	100 / 100	137 ms	21260 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
#define F first
#define S second
#define Pb push_back
using namespace std;
const int N=2e5+5;
long long res,X,n,m,l,ko,Y,Res,f[N];
vector < pair < long long  , long long > > v[N];
vector < long long > V,G;

void Dfs(long long x,long long p,long long val,long long j) {
    if (res<=val) { X=x; res=val; }
    f[x]=j;
    for (int i=0; i<v[x].size(); i++)
        if (f[v[x][i].F]!=j && v[x][i].F!=p) Dfs(v[x][i].F,x,val+v[x][i].S,j);
}

void Df(long long x,long long p,long long val,long long j) {
    if (ko) { V.push_back(val); return ; }
    if (x==Y) { ko=1; return ; }
    f[x]=j;
    for (int i=0; i<v[x].size(); i++)
        if (f[v[x][i].F]!=j && v[x][i].F!=p) {
            Df(v[x][i].F,x,val+v[x][i].S,j);
            if (ko) { V.push_back(val); return ; }
        }
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	int n=N,m=M,l=L;
	 for (int i=0; i<m; i++) {
        v[A[i]].Pb({B[i],T[i]});
        v[B[i]].Pb({A[i],T[i]});
    }
    
    for (int i=0; i<n; i++)
        if (!f[i]) {
            V.clear();
            res=0,X=0,Y=0,ko=0;
            Dfs(i,i,0,1);
            res=0,Y=X;
            Dfs(X,X,0,2);
            Res=max(Res,res);
            Df(X,X,0,3);

            long long Nq=1e13;
            for (int j=0; j<V.size(); j++)
                Nq=min(Nq,max(res-V[j],V[j]));

            if (Nq==1e13) Nq=0;
            G.push_back(Nq);
        }
        
    sort(G.begin(),G.end());

    if (G.size()==1) { return Res; return 0; }
    if (G.size()==2) { return max(Res,G[0]+G[1]+l); return 0; }

    return max(Res,max(G[G.size()-1]+G[G.size()-2]+l,G[G.size()-3]+G[G.size()-2]+2*l));
}

Compilation message (stderr)

dreaming.cpp: In function 'void Dfs(long long int, long long int, long long int, long long int)':
dreaming.cpp:15:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<v[x].size(); i++)
                   ~^~~~~~~~~~~~
dreaming.cpp: In function 'void Df(long long int, long long int, long long int, long long int)':
dreaming.cpp:23:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i<v[x].size(); i++)
                   ~^~~~~~~~~~~~
dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:48:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int j=0; j<V.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