Cod sursa(job #1433840)

Utilizator gabrielinelusGabriel-Robert Inelus gabrielinelus Data 10 mai 2015 00:33:01
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.68 kb
#include <cstdio>
#include <algorithm>
#include <set>
#include <vector>

#define Nmax 50005
#define INF 0x3f3f3f3f
#define DIM 666013

char buffer[DIM];
int poz = DIM - 1;

void Scanf(int &A){
    A = 0;
    while('0' > buffer[poz] || buffer[poz] >'9')
        if(++poz == DIM) fread(buffer,1,DIM,stdin),poz = 0;
    while('0' <= buffer[poz] && buffer[poz] <= '9'){
        A = A * 10 + buffer[poz] - 48;
        if(++poz == DIM) fread(buffer,1,DIM,stdin),poz = 0;
    }
}

using namespace std;

vector<pair<int,int> > G[Nmax];
vector<int> DP;
set<pair<int,int> > H;
int N,M;

void Read()
{
    Scanf(N);Scanf(M);
    DP.resize(N+1);
    int a,b,c;
    for(int i = 1; i <= M; ++i){
        Scanf(a);Scanf(b);Scanf(c);
        G[a].push_back(make_pair(c,b));
    }
}

void Dijkstra(int k)
{
    int cost = 0;
    fill(DP.begin(),DP.end(),INF);
    DP[k] = 0;
    H.insert(make_pair(0,k));
    while(!H.empty())
    {
        k = H.begin()->second;
        cost = H.begin()->first;
        H.erase(H.begin());
        for(auto it : G[k]){
            if(DP[it.second] <= DP[k] + it.first)
                continue;
            if(H.find(make_pair(DP[it.second],it.second)) != H.end())
                H.erase(H.find(make_pair(DP[it.second],it.second)));
            DP[it.second] = DP[k] + it.first;
            H.insert(make_pair(DP[it.second],it.second));
        }
    }
    for(int i = 2; i <= N; ++i)
        if(DP[i] == INF)
            printf("0 ");
        else
            printf("%d ",DP[i]);
}

int main()
{
    freopen("dijkstra.in","r",stdin);
    freopen("dijkstra.out","w",stdout);

    Read();
    Dijkstra(1);

    return 0;
}