Submission #31163

#	Time	Username	Problem	Language	Result	Execution time	Memory
31163		cscandkswon	Dreaming (IOI13_dreaming)	C++14	100 / 100	142 ms	14200 KiB

dreaming

#include "dreaming.h"
#include <bits/stdc++.h>
using namespace std;
const int MAXN=100005;
bool vst[MAXN], chk[MAXN];
vector< pair<int, int> > edge[MAXN];
int dep[MAXN], lng[MAXN], radious;
vector<int> rad;

void dfs1(int nod){
    int i;
    vst[nod]=1, chk[nod]=1;
    for(i=0; i<edge[nod].size(); i++) if(!vst[edge[nod][i].first])
        dfs1(edge[nod][i].first);
    for(i=0; i<edge[nod].size(); i++) if(!vst[edge[nod][i].first])
        dep[nod]=max(dep[nod], dep[edge[nod][i].first]+edge[nod][i].second);
    vst[nod]=0;
}

void dfs2(int nod, int rt){
    int i, dis, mx1=0, mx2=0, idx1;
    vst[nod]=1;
    chk[nod]=1;
    for(i=0; i<edge[nod].size(); i++)if(!vst[edge[nod][i].first]){
        dis=dep[edge[nod][i].first]+edge[nod][i].second;
        if(dis>mx1)
            mx2=mx1, mx1=dis, idx1=i;
        else if(dis>mx2)
            mx2=dis;
    }
    lng[nod]=mx1+max(rt, mx2);
    if(max(mx1, rt)<radious)
        radious=max(mx1, rt);
    for(i=0; i<edge[nod].size(); i++)if(!vst[edge[nod][i].first]){
        if(i==idx1)
            dfs2(edge[nod][i].first, max(rt, mx2)+edge[nod][i].second);
        else
            dfs2(edge[nod][i].first, max(rt, mx1)+edge[nod][i].second);
    }
    vst[nod]=0;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    int i, dia=0;
    for(i=0; i<M; i++){
        edge[A[i]].push_back(make_pair(B[i], T[i]));
        edge[B[i]].push_back(make_pair(A[i], T[i]));
    }
    for(i=0; i<N; i++) if(!chk[i])
        dfs1(i);
    memset(chk, 0, sizeof chk);
    for(i=0; i<N; i++) if(!chk[i]){
        radious=2e9;
        dfs2(i, 0);
        rad.push_back(radious);
    }
    sort(rad.begin(), rad.end(), greater<int>());
    for(i=0; i<N; i++) dia=max(dia, lng[i]);
    if(rad.size()==1)
        return dia;
    else if(rad.size()==2)
        return max(dia, rad[0]+rad[1]+L);
    else
        return max(dia, max(rad[0]+rad[1]+L, rad[1]+rad[2]+L*2));
}

Compilation message (stderr)

dreaming.cpp: In function 'void dfs1(int)':
dreaming.cpp:13:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<edge[nod].size(); i++) if(!vst[edge[nod][i].first])
              ~^~~~~~~~~~~~~~~~~
dreaming.cpp:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<edge[nod].size(); i++) if(!vst[edge[nod][i].first])
              ~^~~~~~~~~~~~~~~~~
dreaming.cpp: In function 'void dfs2(int, int)':
dreaming.cpp:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<edge[nod].size(); i++)if(!vst[edge[nod][i].first]){
              ~^~~~~~~~~~~~~~~~~
dreaming.cpp:34:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i<edge[nod].size(); i++)if(!vst[edge[nod][i].first]){
              ~^~~~~~~~~~~~~~~~~
dreaming.cpp:35:9: warning: 'idx1' may be used uninitialized in this function [-Wmaybe-uninitialized]
         if(i==idx1)
         ^~

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