Cod sursa(job #2500129)

Utilizator st_marianStoica Marian st_marian Data 27 noiembrie 2019 11:49:26
Problema Algoritmul lui Dijkstra Scor 90
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.9 kb
#include <bits/stdc++.h>
#define NMAX 50005
#define cin fin
#define cout fout

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

using namespace std;
InParser fin("dijkstra.in");
ofstream fout("dijkstra.out");
int n, m, p;
int x, y, cost;

int d[NMAX];
vector< pair<int, int> > a[NMAX]; //nod, cost
queue< int > coada;

void read();
void BFS();
int main()
{
    read();

    coada.push(p);

    BFS();

    for(int i=2; i<=n; ++i)
    {
        cout<<d[i]<<' ';
    }
    return 0;
}
void BFS()
{
    while(!coada.empty())
    {
        int first=coada.front();
        coada.pop();

        for(int i=0; i<a[first].size(); ++i)
        {
            int nod=a[first][i].first;
            int c=a[first][i].second;

            if(d[nod]>d[first]+c || d[nod]==0)
            {
                d[nod]=d[first]+c;
                coada.push(nod);
            }
        }
    }
}
void read()
{
    cin>>n>>m;
    for(int i=1; i<=m; ++i)
    {
        cin>>x>>y>>cost;
        a[x].push_back({y, cost});
    }
    p=1;
}