Add K-D Tree (#3210)

src/test/java/com/thealgorithms/datastructures/trees/KDTreeTest.java

@@ -0,0 +1,64 @@
+package com.thealgorithms.datastructures.trees;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class KDTreeTest {
+
+    KDTree.Point pointOf(int x, int y) {
+        return new KDTree.Point(new int[]{x, y});
+    }
+
+    @Test
+    void findMin() {
+        int[][] coordinates = {
+                {30, 40},
+                {5, 25},
+                {70, 70},
+                {10, 12},
+                {50, 30},
+                {35, 45}
+        };
+        KDTree kdTree = new KDTree(coordinates);
+
+        assertEquals(5, kdTree.findMin(0).getCoordinate(0));
+        assertEquals(12, kdTree.findMin(1).getCoordinate(1));
+    }
+
+    @Test
+    void delete() {
+        int[][] coordinates = {
+                {30, 40},
+                {5, 25},
+                {70, 70},
+                {10, 12},
+                {50, 30},
+                {35, 45}
+        };
+        KDTree kdTree = new KDTree(coordinates);
+
+        kdTree.delete(pointOf(30, 40));
+        assertEquals(35, kdTree.getRoot().getPoint().getCoordinate(0));
+        assertEquals(45, kdTree.getRoot().getPoint().getCoordinate(1));
+    }
+
+    @Test
+    void findNearest() {
+        int[][] coordinates = {
+                {2, 3},
+                {5, 4},
+                {9, 6},
+                {4, 7},
+                {8, 1},
+                {7, 2}
+        };
+        KDTree kdTree = new KDTree(coordinates);
+
+        assertEquals(pointOf(7, 2), kdTree.findNearest(pointOf(7, 2)));
+        assertEquals(pointOf(8, 1), kdTree.findNearest(pointOf(8, 1)));
+        assertEquals(pointOf(2, 3), kdTree.findNearest(pointOf(1, 1)));
+        assertEquals(pointOf(5, 4), kdTree.findNearest(pointOf(5, 5)));
+    }
+
+}