Create Dijkstra.cpp

C++/Dijkstra.cpp

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+#include <iostream>
+#include <vector>
+#include <queue>
+#include <climits>
+
+using namespace std;
+
+typedef pair<int, int> pii; // pair to represent (distance, node)
+
+// Dijkstra's Algorithm
+void dijkstra(int source, vector<vector<pii>>& adjList, int V) {
+    // Min-heap priority queue to store (distance, vertex)
+    priority_queue<pii, vector<pii>, greater<pii>> pq;
+
+    // Vector to store shortest distances initialized to infinity
+    vector<int> dist(V, INT_MAX);
+
+    // Start with the source node, distance = 0
+    dist[source] = 0;
+    pq.push({0, source});
+
+    while (!pq.empty()) {
+        int u = pq.top().second; // Get the node with the smallest distance
+        pq.pop();
+
+        // Traverse all adjacent vertices of the current node
+        for (auto edge : adjList[u]) {
+            int v = edge.second;  // Adjacent node
+            int weight = edge.first;  // Edge weight
+
+            // Relaxation step
+            if (dist[u] + weight < dist[v]) {
+                dist[v] = dist[u] + weight;
+                pq.push({dist[v], v});
+            }
+        }
+    }
+
+    // Output shortest distances
+    cout << "Shortest distances from source " << source << ":\n";
+    for (int i = 0; i < V; ++i) {
+        cout << "Vertex " << i << " -> Distance: " << dist[i] << endl;
+    }
+}
+
+int main() {
+    int V = 5; // Number of vertices
+    vector<vector<pii>> adjList(V);
+
+    // Add edges (weight, node)
+    adjList[0].push_back({10, 1});
+    adjList[0].push_back({5, 3});
+    adjList[1].push_back({1, 2});
+    adjList[1].push_back({2, 3});
+    adjList[2].push_back({4, 4});
+    adjList[3].push_back({3, 2});
+    adjList[3].push_back({9, 4});
+    adjList[4].push_back({7, 0});
+
+    int source = 0;
+    dijkstra(source, adjList, V);
+
+    return 0;
+}