Cod sursa(job #2943221)

Utilizator CipriEuCruceanu Ciprian Constantin CipriEu Data 20 noiembrie 2022 18:55:19
Problema Algoritmul lui Dijkstra Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.64 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");
int n, m, p, x, y, c, v[100001], d[100001];
const int inf = 0x3F3F3F3F;
struct arc {int dest, cost = inf;};
vector<arc> a[100001];
vector<int> heap;
void heapify(int root){
    int l = 2*root+1;
    int r = 2*root+2;
    int minim = root;
    if(l<heap.size() && d[heap[l]] < d[heap[minim]]) minim = l;
    if(r<heap.size() && d[heap[r]] < d[heap[minim]]) minim = r;
    if(minim != root){
        swap(heap[root], heap[minim]);
        heapify(minim);
    }
}
void initial(){for(int i=(heap.size()-1)/2; i>=0; i--) heapify(i);}
void delet(){
    swap(heap[0], heap[heap.size()-1]);
    heap.pop_back();
    if(heap.size()) initial();
}
int main()
{
    fin>>n>>m;
    for(int i=1; i<=m; i++){
        fin>>x>>y>>c;
        arc temp;
        temp.cost = c;
        temp.dest = y;
        a[x].push_back(temp);
        temp.dest = x;
        a[y].push_back(temp);
    }
    for(int i=1; i<=n; i++){
        if(i!=p) heap.push_back(i);
        d[i] = inf;
    }
    for(int i=0; i<a[1].size(); i++)
        d[a[1][i].dest] = a[1][i].cost;
    v[1] = 1, d[1] = 0;
    initial();
    while(heap.size()){
        int pmin = heap[0];
        v[pmin] = 1;
        for(int i=0; i<a[pmin].size(); i++){
            int dest = a[pmin][i].dest;
            int cost = a[pmin][i].cost;
            if(!v[dest] && d[dest] > d[pmin] + cost) d[dest] = d[pmin] + cost;
        }
        delet();
    }
    for(int i=2; i<=n; i++)
        fout<<(d[i]==inf?0:d[i])<<" ";
}