Submission #7710

#	Time	Username	Problem	Language	Result	Execution time	Memory
7710		baneling100	Race (IOI11_race)	C++98	100 / 100	891 ms	37448 KiB

race

#include "race.h"
#include <algorithm>
#include <vector>
#include <queue>
#define INF 0x7fffffff

using namespace std;

typedef pair <int,int> ppair;
static vector <ppair> A[200000];
static vector <ppair> Length;
static vector <int> Eraser;
static int N, K, Die[200000], Check[200000], D[1000001];
static int Num, Center, Ans=INF;

int HowManyNode(int Now) {

    int i, j=A[Now].size(), Temp=1;

    Check[Now]=1;
    for(i=0 ; i<j ; i++)
        if(!Die[A[Now][i].first] && !Check[A[Now][i].first])
            Temp+=HowManyNode(A[Now][i].first);
    Check[Now]=0;
    return Temp;
}

int FindCenter(int Now) {

    int i, j=A[Now].size(), OK=1, Sum=1, Temp;

    Check[Now]=1;
    for(i=0 ; i<j ; i++)
        if(!Die[A[Now][i].first] && !Check[A[Now][i].first]) {
            Temp=FindCenter(A[Now][i].first);
            Sum+=Temp;
            if(Temp>Num/2)
                OK=0;
        }
    Check[Now]=0;
    if(Num-Sum>Num/2)
        OK=0;
    if(OK)
        Center=Now;
    return Sum;
}

void FindLength(int Now, int Len, int Lev) {

    int i, j=A[Now].size();

    Check[Now]=1;
    if(Len<=K)
        Length.push_back(make_pair(Len,Lev));
    for(i=0 ; i<j ; i++)
        if(!Die[A[Now][i].first] && !Check[A[Now][i].first])
            FindLength(A[Now][i].first,Len+A[Now][i].second,Lev+1);
    Check[Now]=0;
}

void DivideConquer(int Route) {

    int i, j=A[Route].size(), k, l, Temp;

    Eraser.clear();
    for(i=0 ; i<j ; i++)
        if(!Die[A[Route][i].first]) {
            Length.clear();
            FindLength(A[Route][i].first,A[Route][i].second,1);
            l=Length.size();
            for(k=0 ; k<l ; k++)
                if(D[K-Length[k].first] || Length[k].first==K)
                    if(Ans>Length[k].second+D[K-Length[k].first])
                        Ans=Length[k].second+D[K-Length[k].first];
            for(k=0 ; k<l ; k++) {
                if(!D[Length[k].first]) {
                    Eraser.push_back(Length[k].first);
                    D[Length[k].first]=Length[k].second;
                }
                else if(D[Length[k].first]>Length[k].second)
                    D[Length[k].first]=Length[k].second;
            }
        }
    l=Eraser.size();
    for(k=0 ; k<l ; k++)
        D[Eraser[k]]=0;
    for(i=0 ; i<j ; i++)
        if(!Die[A[Route][i].first]) {
            Num=HowManyNode(A[Route][i].first);
            Temp=FindCenter(A[Route][i].first);
            Die[Center]=1;
            DivideConquer(Center);
        }
}

int best_path(int N_, int K_, int H[][2], int L[]) {

    int i, Temp;

    N=N_;
    K=K_;
    for(i=0 ; i<N-1 ; i++) {
        A[H[i][0]].push_back(make_pair(H[i][1],L[i]));
        A[H[i][1]].push_back(make_pair(H[i][0],L[i]));
    }
    Num=HowManyNode(0);
    Temp=FindCenter(0);
    Die[Center]=1;
    DivideConquer(Center);
    if(Ans==INF)
        return -1;
    return Ans;
}

Compilation message (stderr)

race.cpp: In function 'void DivideConquer(int)':
race.cpp:63:37: warning: variable 'Temp' set but not used [-Wunused-but-set-variable]
     int i, j=A[Route].size(), k, l, Temp;
                                     ^~~~
race.cpp: In function 'int best_path(int, int, int (*)[2], int*)':
race.cpp:98:12: warning: variable 'Temp' set but not used [-Wunused-but-set-variable]
     int i, Temp;
            ^~~~

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57