Cod sursa(job #2198579)

Utilizator cristiP97Prodan Cristian cristiP97 Data 24 aprilie 2018 18:43:13
Problema Algoritmul Bellman-Ford Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.8 kb
#include <fstream>
#include <vector>
#include <algorithm>
#include <iostream>
#include <queue>

using namespace std;
ifstream in("bellmanford.in");

struct drumuri {
    int sursa,destinatie,cost;
};

const int knmax = 50005;
const int INF = 999999999;
vector <drumuri> adj;
int d[knmax];

void citire(int m){

    int nod1,nod2,cost;
    for(int i = 1; i<= m; ++i) {
    	drumuri drum; 
        in >> nod1 >> nod2 >> cost;
        drum.sursa = nod1;
        drum.destinatie = nod2;
        drum.cost = cost;
        adj.push_back(drum);
    }
}

int main() {
    int n,m;
    in >> n >> m;

    citire(m);
    in.close();

	for(int i = 1; i <= n; ++i) {
		d[i] = INF;
	}
	
	for(unsigned int i = 0; i < adj.size(); ++i) {
		if(adj[i].sursa == 1)
			d[adj[i].destinatie] = adj[i].cost;
	}
	
	d[1] = 0;
	
	int perfect[n + 1];
	vector <int> bun;
	
	for(int i = 1; i < n - 1; ++i) {
	
		while(!bun.empty()){
			for(unsigned int j = 0; j < adj.size(); ++j) {
				if( bun.back() == adj[j].sursa) {
					iter_swap(adj.begin() + j, adj.end() - 1);
					adj.pop_back();
				}
			}
			bun.pop_back();
		}
	
		for(unsigned int j = 0; j < adj.size(); ++j) {
			int sursa = adj[j].sursa;
			int destinatie = adj[j].destinatie;
			int cost = adj[j].cost;
			
			if( d[destinatie] > d[sursa] + cost ) {
				d[destinatie] = d[sursa] + cost;
			} else {
				if(perfect[destinatie] != 2) {
					perfect[destinatie] = 1;
					bun.push_back(destinatie);
				}
			}
		}
	}
	
	ofstream out ("bellmanford.out");
	
	for(unsigned int j = 0; j < adj.size(); ++j) {
			int sursa = adj[j].sursa;
			int destinatie = adj[j].destinatie;
			int cost = adj[j].cost;
			
			if( d[destinatie] > d[sursa] + cost ) {
				out << "Ciclu negativ!";
				return 0;
			}
		}
    
    
    for(int i = 2; i <= n; ++i) {
		out << d[i] << " ";
	}
	
	out.close();
    
    
    return 0;
}