Create Dijkstra's Algorithm

Author: rahulsg98

Dijkstra's Algorithm

@@ -0,0 +1,94 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define debug(x) cout<<#x<<" is "<<endl
+
+using ll = long long;
+
+#define x first
+#define y second
+
+template <typename T>
+struct Dijkstra {
+
+	int node,edge;
+	vector< vector< pair<int,T> > > adj;
+	vector< T > level;
+	vector<int> parent;
+
+	Dijkstra(int _node, int _edge) : node(_node), edge(_edge) {
+		vector<int>(node+1).swap(parent);
+		vector<T>(node+1, numeric_limits<T>::max()).swap(level);
+		vector< vector< pair<int,T> > > (node+1).swap(adj);
+	}
+
+	void add_edge(int u, int v, T w) {
+		adj[u].push_back({v,w});
+		adj[v].push_back({u,w});
+	}
+
+	void traverse(int src) {
+
+		level[src] = 0;
+		set< pair<T,int> > s {{0,src}};
+		parent[src] = -1;
+
+		while(not s.empty()) {
+			auto it = *s.begin();
+			int cur_node = it.y;
+			T cur_level = it.x;
+			s.erase(s.begin());
+
+			for(auto u : adj[cur_node]) {
+				if(level[u.x] - u.y > cur_level) {
+					level[u.x] = cur_level + u.y;
+					parent[u.x] = cur_node; 
+					s.insert({level[u.x],u.x});
+				}
+			}
+		}
+	}
+
+	void print_path(int x) {
+
+		if(level[x] == numeric_limits<T>::max()) {
+			cout<<"-1\n";
+			return;
+		}
+
+		if(x == -1){
+			return;
+		}
+
+		print_path(parent[x]);
+		cout<<x<<" ";
+
+	}
+
+};
+
+
+int main(int argc, char const *argv[])
+{
+	ios::sync_with_stdio(false);
+	cin.tie(nullptr);
+
+
+	int node,edge;
+	cin>>node>>edge;
+
+	Dijkstra<ll> d(node,edge);
+
+
+	while(edge--){
+		int x,y;
+		ll w;
+		cin>>x>>y>>w;
+		d.add_edge(x,y,w);
+	}
+
+	d.traverse(1);
+	d.print_path(node);
+
+	return 0;
+}