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| 1 | // | |
| 2 | // Created by Julio Tentor <[email protected]> | |
| 3 | // | |
| 4 | ||
| 5 | public class BinarySearchTree<ELEMENT extends Comparable<ELEMENT>> extends BinaryTree<ELEMENT> {
| |
| 6 | ||
| 7 | ||
| 8 | public BinarySearchTree() {
| |
| 9 | super(); | |
| 10 | } | |
| 11 | ||
| 12 | ||
| 13 | public void add(ELEMENT item) {
| |
| 14 | if (this.root == null) {
| |
| 15 | this.root = new BTNode<ELEMENT>(item, null, null); | |
| 16 | } else {
| |
| 17 | BTNode<ELEMENT> temp = this.root; | |
| 18 | BTNode<ELEMENT> prev = null; | |
| 19 | while (temp != null ) {
| |
| 20 | prev = temp; | |
| 21 | if (item.compareTo(temp.item) < 0) {
| |
| 22 | temp = temp.left; | |
| 23 | } else {
| |
| 24 | temp = temp.right; | |
| 25 | } | |
| 26 | } | |
| 27 | temp = new BTNode<ELEMENT>(item, null, null); | |
| 28 | if (item.compareTo(prev.item) < 0) {
| |
| 29 | prev.left = temp; | |
| 30 | } else {
| |
| 31 | prev.right = temp; | |
| 32 | } | |
| 33 | } | |
| 34 | } | |
| 35 | ||
| 36 | ||
| 37 | public ELEMENT remove(ELEMENT item) {
| |
| 38 | return removeByCopy(item); | |
| 39 | //return removeByFusion(item); | |
| 40 | } | |
| 41 | ||
| 42 | ||
| 43 | private ELEMENT removeByCopy(ELEMENT item) {
| |
| 44 | BTNode<ELEMENT> find = this.root; | |
| 45 | BTNode<ELEMENT> prev = null; | |
| 46 | while ((find != null) && (find.item.compareTo(item) != 0)) {
| |
| 47 | prev = find; | |
| 48 | if (item.compareTo(find.item) < 0) {
| |
| 49 | find = find.left; | |
| 50 | } else {
| |
| 51 | find = find.right; | |
| 52 | } | |
| 53 | } | |
| 54 | if (find == null) {
| |
| 55 | throw new RuntimeException("No existe el elemento o el árbol está vacío");
| |
| 56 | } // find es el nodo con el valor a extraer y prev el padre de ese nodo | |
| 57 | ELEMENT save = find.item; | |
| 58 | BTNode<ELEMENT> node = find; | |
| 59 | if (node.right == null) { // no hay subarbol derecho
| |
| 60 | node = node.left; // nodo con un descendiente u hoja | |
| 61 | } else {
| |
| 62 | if (node.left == null) { // no hay subarbol izquierdo
| |
| 63 | node = node.right; // nodo con un descendiente u hoja | |
| 64 | } else { // dos descendientes
| |
| 65 | BTNode<ELEMENT> last = node; | |
| 66 | BTNode<ELEMENT> temp = node.right; // a la derecha (mayores) | |
| 67 | while (temp.left != null) { // busca a la izquierda el menor
| |
| 68 | last = temp; | |
| 69 | temp = temp.left; | |
| 70 | } | |
| 71 | // temp es el menor de los mayores | |
| 72 | node.item = temp.item; // hace la copia | |
| 73 | if (last == node) {
| |
| 74 | last.right = temp.right; | |
| 75 | } else {
| |
| 76 | last.left = temp.right; | |
| 77 | } | |
| 78 | temp.right = null; | |
| 79 | } | |
| 80 | } | |
| 81 | // reajustar el arbol | |
| 82 | if (find == this.root) {
| |
| 83 | this.root = node; | |
| 84 | } else {
| |
| 85 | if (prev.left == find) {
| |
| 86 | prev.left = node; | |
| 87 | } else {
| |
| 88 | prev.right = node; | |
| 89 | } | |
| 90 | } | |
| 91 | return save; | |
| 92 | } | |
| 93 | ||
| 94 | ||
| 95 | private ELEMENT removeByFusion(ELEMENT item) {
| |
| 96 | BTNode<ELEMENT> find = this.root; | |
| 97 | BTNode<ELEMENT> prev = null; | |
| 98 | while ((find != null) && (find.item.compareTo(item) != 0)) {
| |
| 99 | prev = find; | |
| 100 | if (item.compareTo(find.item) < 0) {
| |
| 101 | find = find.left; | |
| 102 | } else {
| |
| 103 | find = find.right; | |
| 104 | } | |
| 105 | } | |
| 106 | if (find == null) {
| |
| 107 | throw new RuntimeException("No existe el elemento o el árbol está vacío");
| |
| 108 | } | |
| 109 | ELEMENT save = find.item; | |
| 110 | BTNode<ELEMENT> node = find; | |
| 111 | if (node.right == null) {
| |
| 112 | node = node.left; | |
| 113 | } else {
| |
| 114 | if (node.left == null) {
| |
| 115 | node = node.right; | |
| 116 | } else {
| |
| 117 | BTNode<ELEMENT> temp = node.right; | |
| 118 | while (temp.left != null) {
| |
| 119 | temp = temp.left; | |
| 120 | } | |
| 121 | temp.left = node.left; | |
| 122 | node = node.right; | |
| 123 | } | |
| 124 | } | |
| 125 | if (find == this.root) {
| |
| 126 | this.root = node; | |
| 127 | } else {
| |
| 128 | if (prev.left == find) {
| |
| 129 | prev.left = node; | |
| 130 | } else {
| |
| 131 | prev.right = node; | |
| 132 | } | |
| 133 | } | |
| 134 | find.left = find.right = null; | |
| 135 | return save; | |
| 136 | } | |
| 137 | ||
| 138 | } | |
| 139 |