Submission #37942

#	Time	Username	Problem	Language	Result	Execution time	Memory
37942		14kg	Dreaming (IOI13_dreaming)	C++11	100 / 100	119 ms	13688 KiB

dreaming

#include "dreaming.h"
#include <vector>
#include <algorithm>
#define N 100001
#define INF 2000000000

using namespace std;
int n, L, out, max_len, MAX[4], gd[N];
bool check[N], gd_check[N];
vector<pair<int,int> > r[N];

int max_f(int x, int y) { return x>y?x:y; }
int min_f(int x, int y) { return x<y?x:y; }

int g(int lev, int up_node){
    if(!gd_check[lev]){
        gd_check[lev]=true;
        for(vector<pair<int,int> >::iterator it=r[lev].begin(); it!=r[lev].end(); it++)
            if(it->first!=up_node) gd[lev]=max_f(gd[lev],it->second+g(it->first,lev));
    }
    return gd[lev];
}
void f(int lev, int up_len){
    int max1=0, max2=0, path, temp;

    check[lev]=true;
    for(vector<pair<int,int> >::iterator it=r[lev].begin(); it!=r[lev].end(); it++) {
        if(!check[it->first]) temp=g(it->first,lev)+it->second;
        else temp=up_len;

        if(max1<temp){
            max2=max1, max1=temp;
            path=it->first;
        }
        else if(max2<temp) max2=temp;
    }
    out=max_f(out,max1+max2);
    max_len=min_f(max_len,max1);

    for(vector<pair<int,int> >::iterator it=r[lev].begin(); it!=r[lev].end(); it++)
        if(!check[it->first]) f(it->first,(path==it->first?max2:max1)+it->second);
}

int travelTime(int _n, int m, int _L, int _a[], int _b[], int _t[]) {
    int x, y, cnt=0;

    n=_n, L=_L;
    for(int i=0; i<m; i++){
        x=_a[i]+1, y=_b[i]+1;
        r[x].push_back({y,_t[i]}), r[y].push_back({x,_t[i]});
    }

    for(int i=1; i<=n; i++)
        if(!check[i]){
            max_len=INF, f(i,0);

            cnt++;
            MAX[0]=max_len, sort(MAX+0,MAX+4);
        }
    return max_f(out,max_f(cnt>1?MAX[3]+MAX[2]+L:0,cnt>2?MAX[2]+MAX[1]+L+L:0));
}

Compilation message (stderr)

dreaming.cpp: In function 'void f(int, int)':
dreaming.cpp:41:59: warning: 'path' may be used uninitialized in this function [-Wmaybe-uninitialized]
         if(!check[it->first]) f(it->first,(path==it->first?max2:max1)+it->second);
                                           ~~~~~~~~~~~~~~~~^~~~~~~~~~~

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