Initial commit

Practical-Teaching/Data-Sructure/Big/3/3.4.cpp

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+#include <iostream>
+#include <vector>
+#include <climits>
+
+using namespace std;
+
+#define INF INT_MAX
+#define N 6
+
+void Dijkstra(int graph[N][N], int start) {
+	vector<int> dist(N, INF);
+	dist[start] = 0;
+	vector<bool> visited(N, false);
+	vector<int> prev(N, -1);
+
+	for (int count = 0; count < N - 1; count++) {
+		int min = INF, min_index;
+		for (int v = 0; v < N; v++)
+			if (!visited[v] && dist[v] <= min)
+				min = dist[v], min_index = v;
+
+		int u = min_index;
+		visited[u] = true;
+
+		for (int v = 0; v < N; v++)
+			if (!visited[v] && graph[u][v] && dist[u] != INF && dist[u] + graph[u][v] < dist[v]) {
+				dist[v] = dist[u] + graph[u][v];
+				prev[v] = u;
+			}
+	}
+
+	for (int i = 0; i < N; i++) {
+		if (i != start) {
+			cout << "Path from " << start << " to " << i << ": ";
+			if (dist[i] == INF) {
+				cout << "No path\n";
+			}
+			else {
+				vector<int> path;
+				for (int j = i; j != -1; j = prev[j])
+					path.push_back(j);
+				for (int j = path.size() - 1; j > 0; j--)
+					cout << path[j] << " -> ";
+				cout << path[0] << " (Cost: " << dist[i] << ")\n";
+			}
+		}
+	}
+}
+
+int main() {
+	int graph[N][N] = {
+		{ 0, 0, 10, 0, 30, 100 },
+		{ 0, 0, 5, 0, 0, 0 },
+		{ 0, 0, 0, 50, 0, 0 },
+		{ 0, 0, 0, 0, 0, 10 },
+		{ 0, 0, 0, 20, 0, 60 },
+		{ 0, 0, 0, 0, 0, 0 }
+	};
+
+	for (int i = 0; i < N; i++)
+		Dijkstra(graph, i);
+
+	return 0;
+}