Cod sursa(job #2026031)

Utilizator al.mocanuAlexandru Mocanu al.mocanu Data 23 septembrie 2017 16:33:03
Problema Algoritmul lui Dijkstra Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.22 kb
#include <fstream>
#include <vector>
#include <queue>
#include <limits.h>
#define pii pair<int, int>
#define mk make_pair
#define f first
#define s second
#define MAX 100005
using namespace std;

struct comp {
    bool operator() (pii a, pii b) {
        return a.s > b.s;
    }
};

int n, m, d[MAX];
int a, b, c;
bool viz[MAX];
vector<pii> l[MAX];

void dijkstra() {
    priority_queue<pii, vector<pii>, comp> q;

    for(int i = 1; i <= n; ++i)
        d[i] = INT_MAX;
    d[1] = 0;
    q.push(mk(d[1], 1));

    while(!q.empty()) {
        int node = q.top().s;
        q.pop();

        if(node == n)
            return;

        if(viz[node])
            continue;
        viz[node] = 1;

        for(int i = 0; i < l[node].size(); ++i)
            if(d[l[node][i].f] > d[node] + l[node][i].s) {
                d[l[node][i].f] = d[node] + l[node][i].s;
                q.push(mk(d[l[node][i].f], l[node][i].f));
            }
    }
}

int main() {
    ifstream f("dijkstra.in");
    ofstream g("dijkstra.out");

    f >> n >> m;
    for(int i = 0; i < m; ++i) {
        f >> a >> b >> c;
        l[a].push_back(mk(b, c));
    }

    dijkstra();

    for(int i = 2; i <= n; ++i)
        g << ((d[i] == INT_MAX) ? 0 : d[i]) << " ";

    return 0;
}