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add comments and remove <bits/stdc++.h>

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Nidheesh Pandey
2017-12-28 19:56:35 +05:30
committed by GitHub
parent feeca86843
commit bc8ef9e8a9
1 changed files with 13 additions and 7 deletions
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20
Graph/Dijkstra.cpp
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@@ -1,16 +1,18 @@
#include<bits/stdc++.h>
#include <queue>
#include <vector>
#include <cstdio>
#include <iostream>
using namespace std;
#define INF 10000010
vector < pair <int,int> > graph[5*100001];
int m,n,l,x,y;
int dis[5*100001];
int dij(vector <pair<int,int> > * v,int s,int * dis) {
priority_queue < pair <int,int> , vector < pair <int,int> >,greater < pair <int,int> > > pq;
// source distance to zero.
pq.push(make_pair(0,s));
dis[s] = 0;
int u;
while(!pq.empty()) {
u = (pq.top()).second;
pq.pop();
for( vector <pair <int,int> > :: iterator it = v[u].begin(); it != v[u].end();it++) {
@@ -22,19 +24,23 @@ int dij(vector <pair<int,int> > * v,int s,int * dis) {
}
}
int main() {
int m,n,l,x,y,s;
// n--> number of nodes , m --> number of edges
cin>>n>>m;
for(int i = 0;i < m;i++) {
// input edges.
scanf("%d%d%d",&x,&y,&l);
graph[x].push_back(make_pair(l,y));
graph[y].push_back(make_pair(l,x));
graph[y].push_back(make_pair(l,x)); // comment this line for directed graph
}
// start node.
scanf("%d",&s);
for(int i = 0;i < n;i++)
// intialise all distances to infinity.
for(int i = 1;i <= n;i++)
dis[i] = INF;
dij(graph,s,dis);
for(int i = 0;i < n;i++)
for(int i = 1;i <= n;i++)
if(dis[i] == INF)
cout<<"-1 ";
else