From e7ec93a72a665acbbc0aeda932c8657152e75810 Mon Sep 17 00:00:00 2001
From: Sourav Sharma <51079951+neoneww@users.noreply.github.com>
Date: Thu, 21 Oct 2021 11:14:35 +0530
Subject: [PATCH] Create floyd_warshall.cpp

---
 floyd_warshall.cpp | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 floyd_warshall.cpp

diff --git a/floyd_warshall.cpp b/floyd_warshall.cpp
new file mode 100644
index 0000000..1893aef
--- /dev/null
+++ b/floyd_warshall.cpp
@@ -0,0 +1,57 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#define V 6 // No of vertices
+
+void floyd_warshall(int graph[V][V])
+{
+    int dist[V][V];
+
+    // Assign all values of graph to allPairs_SP
+    for (int i = 0; i < V; ++i)
+        for (int j = 0; j < V; ++j)
+            dist[i][j] = graph[i][j];
+
+    // Find all pairs shortest path by trying all possible paths
+    for (int k = 0; k < V; ++k)         // Try all intermediate nodes
+        for (int i = 0; i < V; ++i)     // Try for all possible starting position
+            for (int j = 0; j < V; ++j) // Try for all possible ending position
+            {
+                if (dist[i][k] == INT_MAX || dist[k][j] == INT_MAX) // SKIP if K is unreachable from i or j is unreachable from k
+                    continue;
+                else if (dist[i][k] + dist[k][j] < dist[i][j]) // Check if new distance is shorter via vertex K
+                    dist[i][j] = dist[i][k] + dist[k][j];
+            }
+
+    // Check for negative edge weight cycle
+    for (int i = 0; i < V; ++i)
+        if (dist[i][i] < 0)
+        {
+            cout << "Negative edge weight cycle is present\n";
+            return;
+        }
+
+    // Print Shortest Path Graph
+    //(Values printed as INT_MAX defines there is no path)
+    for (int i = 1; i < V; ++i)
+    {
+        for (int j = 0; j < V; ++j)
+            cout << i << " to " << j << " distance is " << dist[i][j] << "\n";
+        cout << "=================================\n";
+    }
+}
+
+int main()
+{
+    int graph[V][V] = {{0, 1, 4, INT_MAX, INT_MAX, INT_MAX},
+                       {INT_MAX, 0, 4, 2, 7, INT_MAX},
+                       {INT_MAX, INT_MAX, 0, 3, 4, INT_MAX},
+                       {INT_MAX, INT_MAX, INT_MAX, 0, INT_MAX, 4},
+                       {INT_MAX, INT_MAX, INT_MAX, 3, 0, INT_MAX},
+                       {INT_MAX, INT_MAX, INT_MAX, INT_MAX, 5, 0}};
+
+    floyd_warshall(graph);
+    return 0;
+}
+
+// TIME COMPLEXITY: O(V^3)