Extend Graph Algorithms: Added Two Popular Algorithms: BronKerbosch, EdmondsKarp (#6576)

* Bron–Kerbosch algorithm added.

* test:Bron–Kerbosch algorithm added.

* lint checked.

* clang-format linting checked.

* lint checked in remote

Removed duplicate import statements for assertions.

* Remove unnecessary blank line in BronKerboschTest

* EdmondsKarp algorithm added.

* reformatted

---------

Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>

src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java

@@ -0,0 +1,48 @@
+package com.thealgorithms.graph;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class EdmondsKarpTest {
+
+    @Test
+    @DisplayName("Classic CLRS network yields max flow 23")
+    void clrsExample() {
+        int[][] capacity = {{0, 16, 13, 0, 0, 0}, {0, 0, 10, 12, 0, 0}, {0, 4, 0, 0, 14, 0}, {0, 0, 9, 0, 0, 20}, {0, 0, 0, 7, 0, 4}, {0, 0, 0, 0, 0, 0}};
+        int maxFlow = EdmondsKarp.maxFlow(capacity, 0, 5);
+        assertEquals(23, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Disconnected network has zero flow")
+    void disconnectedGraph() {
+        int[][] capacity = {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}};
+        int maxFlow = EdmondsKarp.maxFlow(capacity, 0, 2);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Source equals sink returns zero")
+    void sourceEqualsSink() {
+        int[][] capacity = {{0, 5}, {0, 0}};
+        int maxFlow = EdmondsKarp.maxFlow(capacity, 0, 0);
+        assertEquals(0, maxFlow);
+    }
+
+    @Test
+    @DisplayName("Invalid matrix throws exception")
+    void invalidMatrix() {
+        int[][] capacity = {{0, 1}, {1}};
+        assertThrows(IllegalArgumentException.class, () -> EdmondsKarp.maxFlow(capacity, 0, 1));
+    }
+
+    @Test
+    @DisplayName("Negative capacity is rejected")
+    void negativeCapacity() {
+        int[][] capacity = {{0, -1}, {0, 0}};
+        assertThrows(IllegalArgumentException.class, () -> EdmondsKarp.maxFlow(capacity, 0, 1));
+    }
+}