规范：节点size不小于兄弟节点的任意一个子节点size（不能比侄子小）
package com.newcoder;public class SizeBalancedTreeMap { public static class SBTNode , V> { public K key; public V value; public SBTNode l; public SBTNode r; public int size; public SBTNode(K key, V value) { this.key = key; this.value = value; size = 1; } } public static class SizeBalancedTreeMap , V> { private SBTNode root; private SBTNode rightRotate(SBTNode cur) { SBTNode leftNode = cur.l; cur.l = leftNode.r; leftNode.r = cur; leftNode.size = cur.size; cur.size = (cur.l != null ? cur.l.size : 0) + (cur.r != null ? cur.r.size : 0) + 1; return leftNode; } private SBTNode leftRotate(SBTNode cur) { SBTNode rightNode = cur.r; cur.r = rightNode.l; rightNode.l = cur; rightNode.size = cur.size; cur.size = (cur.l != null ? cur.l.size : 0) + (cur.r != null ? cur.r.size : 0) + 1; return rightNode; } private SBTNode matain(SBTNode cur) { if (cur == null) { return null; } if (cur.l != null && cur.l.l != null && cur.r != null && cur.l.l.size > cur.r.size) { cur = rightRotate(cur); cur.r = matain(cur.r); cur = matain(cur); } else if (cur.l != null && cur.l.r != null && cur.r != null && cur.l.r.size > cur.r.size) { cur.l = leftRotate(cur.l); cur = rightRotate(cur); cur.l = matain(cur.l); cur.r = matain(cur.r); cur = matain(cur); } else if (cur.r != null && cur.r.r != null && cur.l != null && cur.r.r.size > cur.l.size) { cur = leftRotate(cur); cur.l = matain(cur.l); cur = matain(cur); } else if (cur.r != null && cur.r.l != null && cur.l != null && cur.r.l.size > cur.l.size) { cur.r = rightRotate(cur.r); cur = leftRotate(cur); cur.l = matain(cur.l); cur.r = matain(cur.r); cur = matain(cur); } return cur; } private SBTNode findLastIndex(K key) { SBTNode pre = root; SBTNode cur = root; while (cur != null) { pre = cur; if (key.compareTo(cur.key) == 0) { break; } else if (key.compareTo(cur.key) < 0) { cur = cur.l; } else { cur = cur.r; } } return pre; } private SBTNode findLastNoSmallIndex(K key) { SBTNode ans = null; SBTNode cur = root; while (cur != null) { if (key.compareTo(cur.key) == 0) { ans = cur; break; } else if (key.compareTo(cur.key) < 0) { ans = cur; cur = cur.l; } else { cur = cur.r; } } return ans; } private SBTNode findLastNoBigIndex(K key) { SBTNode ans = null; SBTNode cur = root; while (cur != null) { if (key.compareTo(cur.key) == 0) { ans = cur; break; } else if (key.compareTo(cur.key) < 0) { cur = cur.l; } else { ans = cur; cur = cur.r; } } return ans; } private SBTNode add(SBTNode cur, K key, V value) { if (cur == null) { return new SBTNode (key, value); } else { cur.size++; if (key.compareTo(cur.key) < 0) { cur.l = add(cur.l, key, value); } else { cur.r = add(cur.r, key, value); } return matain(cur); } } private SBTNode delete(SBTNode cur, K key) { cur.size--; if (key.compareTo(cur.key) > 0) { cur.r = delete(cur.r, key); } else if (key.compareTo(cur.key) < 0) { cur.l = delete(cur.l, key); } else { if (cur.l == null && cur.r == null) { // free cur memory -> C++ cur = null; } else if (cur.l == null && cur.r != null) { // free cur memory -> C++ cur = cur.r; } else if (cur.l != null && cur.r == null) { // free cur memory -> C++ cur = cur.l; } else { SBTNode pre = null; SBTNode des = cur.r; des.size--; while (des.l != null) { pre = des; des = des.l; des.size--; } if (pre != null) { pre.l = des.r; des.r = cur.r; } des.l = cur.l; des.size = des.l.size + des.r.size + 1; // free cur memory -> C++ cur = des; } } return cur; } private SBTNode getIndex(SBTNode cur, int kth) { if (kth == (cur.l != null ? cur.l.size : 0) + 1) { return cur; } else if (kth <= (cur.l != null ? cur.l.size : 0)) { return getIndex(cur.l, kth); } else { return getIndex(cur.r, kth - (cur.l != null ? cur.l.size : 0) - 1); } } public int size() { return root == null ? 0 : root.size; } public boolean containsKey(K key) { if (key == null) { throw new RuntimeException("invalid parameter."); } SBTNode lastNode = findLastIndex(key); return lastNode != null && key.compareTo(lastNode.key) == 0 ? true : false; } public void put(K key, V value) { if (key == null) { throw new RuntimeException("invalid parameter."); } SBTNode lastNode = findLastIndex(key); if (lastNode != null && key.compareTo(lastNode.key) == 0) { lastNode.value = value; } else { root = add(root, key, value); } } public void remove(K key) { if (key == null) { throw new RuntimeException("invalid parameter."); } if (containsKey(key)) { root = delete(root, key); } } public K getIndexKey(int index) { if (index < 0 || index >= this.size()) { throw new RuntimeException("invalid parameter."); } return getIndex(root, index + 1).key; } public V getIndexValue(int index) { if (index < 0 || index >= this.size()) { throw new RuntimeException("invalid parameter."); } return getIndex(root, index + 1).value; } public V get(K key) { if (key == null) { throw new RuntimeException("invalid parameter."); } SBTNode lastNode = findLastIndex(key); if (lastNode != null && key.compareTo(lastNode.key) == 0) { return lastNode.value; } else { return null; } } public K firstKey() { if (root == null) { return null; } SBTNode cur = root; while (cur.l != null) { cur = cur.l; } return cur.key; } public K lastKey() { if (root == null) { return null; } SBTNode cur = root; while (cur.r != null) { cur = cur.r; } return cur.key; } public K floorKey(K key) { if (key == null) { throw new RuntimeException("invalid parameter."); } SBTNode lastNoBigNode = findLastNoBigIndex(key); return lastNoBigNode == null ? null : lastNoBigNode.key; } public K ceilingKey(K key) { if (key == null) { throw new RuntimeException("invalid parameter."); } SBTNode lastNoSmallNode = findLastNoSmallIndex(key); return lastNoSmallNode == null ? null : lastNoSmallNode.key; } } // for test public static void printAll(SBTNode head) { System.out.println("Binary Tree:"); printInOrder(head, 0, "H", 17); System.out.println(); } // for test public static void printInOrder(SBTNode head, int height, String to, int len) { if (head == null) { return; } printInOrder(head.r, height + 1, "v", len); String val = to + "(" + head.key + "," + head.value + ")" + to; int lenM = val.length(); int lenL = (len - lenM) / 2; int lenR = len - lenM - lenL; val = getSpace(lenL) + val + getSpace(lenR); System.out.println(getSpace(height * len) + val); printInOrder(head.l, height + 1, "^", len); } // for test public static String getSpace(int num) { String space = " "; StringBuffer buf = new StringBuffer(""); for (int i = 0; i < num; i++) { buf.append(space); } return buf.toString(); } public static void main(String[] args) { SizeBalancedTreeMap sbt = new SizeBalancedTreeMap (); sbt.put("d", 4); sbt.put("c", 3); sbt.put("a", 1); sbt.put("b", 2); // sbt.put("e", 5); sbt.put("g", 7); sbt.put("f", 6); sbt.put("h", 8); sbt.put("i", 9); sbt.put("a", 111); System.out.println(sbt.get("a")); sbt.put("a", 1); System.out.println(sbt.get("a")); for (int i = 0; i < sbt.size(); i++) { System.out.println(sbt.getIndexKey(i) + " , " + sbt.getIndexValue(i)); } printAll(sbt.root); System.out.println(sbt.firstKey()); System.out.println(sbt.lastKey()); System.out.println(sbt.floorKey("g")); System.out.println(sbt.ceilingKey("g")); System.out.println(sbt.floorKey("e")); System.out.println(sbt.ceilingKey("e")); System.out.println(sbt.floorKey("")); System.out.println(sbt.ceilingKey("")); System.out.println(sbt.floorKey("j")); System.out.println(sbt.ceilingKey("j")); sbt.remove("d"); printAll(sbt.root); sbt.remove("f"); printAll(sbt.root); }}