Add KCenters algorithm (#5806)

src/test/java/com/thealgorithms/greedyalgorithms/KCentersTest.java

@@ -0,0 +1,15 @@
+package com.thealgorithms.greedyalgorithms;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class KCentersTest {
+
+    @Test
+    public void testFindKCenters() {
+        int[][] distances = {{0, 2, 3, 4}, {2, 0, 5, 1}, {3, 5, 0, 7}, {4, 1, 7, 0}};
+        assertEquals(4, KCenters.findKCenters(distances, 2));
+        assertEquals(2, KCenters.findKCenters(distances, 4));
+    }
+}