modify code

src/class12/Code04_IsFull.java

@@ -12,56 +12,68 @@ public class Code04_IsFull {
 		}
 	}
 
+	// 第一种方法
+	// 收集整棵树的高度h，和节点数n
+	// 只有满二叉树满足 : 2 ^ h - 1 == n
 	public static boolean isFull1(Node head) {
 		if (head == null) {
 			return true;
 		}
-		int height = h(head);
-		int nodes = n(head);
-		return (1 << height) - 1 == nodes;
+		Info1 all = process1(head);
+		return (1 << all.height) - 1 == all.nodes;
 	}
 
-	public static int h(Node head) {
-		if (head == null) {
-			return 0;
+	public static class Info1 {
+		public int height;
+		public int nodes;
+
+		public Info1(int h, int n) {
+			height = h;
+			nodes = n;
 		}
-		return Math.max(h(head.left), h(head.right)) + 1;
 	}
 
-	public static int n(Node head) {
+	public static Info1 process1(Node head) {
 		if (head == null) {
-			return 0;
+			return new Info1(0, 0);
 		}
-		return n(head.left) + n(head.right) + 1;
+		Info1 leftInfo = process1(head.left);
+		Info1 rightInfo = process1(head.right);
+		int height = Math.max(leftInfo.height, rightInfo.height) + 1;
+		int nodes = leftInfo.nodes + rightInfo.nodes + 1;
+		return new Info1(height, nodes);
 	}
 
+	// 第二种方法
+	// 收集子树是否是满二叉树
+	// 收集子树的高度
+	// 左树满 && 右树满 && 左右树高度一样 -> 整棵树是满的
 	public static boolean isFull2(Node head) {
 		if (head == null) {
 			return true;
 		}
-		Info all = process(head);
-		return (1 << all.height) - 1 == all.nodes;
+		return process2(head).isFull;
 	}
 
-	public static class Info {
+	public static class Info2 {
+		public boolean isFull;
 		public int height;
-		public int nodes;
 
-		public Info(int h, int n) {
+		public Info2(boolean f, int h) {
+			isFull = f;
 			height = h;
-			nodes = n;
 		}
 	}
 
-	public static Info process(Node head) {
-		if (head == null) {
-			return new Info(0, 0);
+	public static Info2 process2(Node h) {
+		if (h == null) {
+			return new Info2(true, 0);
 		}
-		Info leftInfo = process(head.left);
-		Info rightInfo = process(head.right);
+		Info2 leftInfo = process2(h.left);
+		Info2 rightInfo = process2(h.right);
+		boolean isFull = leftInfo.isFull && rightInfo.isFull && leftInfo.height == rightInfo.height;
 		int height = Math.max(leftInfo.height, rightInfo.height) + 1;
-		int nodes = leftInfo.nodes + rightInfo.nodes + 1;
-		return new Info(height, nodes);
+		return new Info2(isFull, height);
 	}
 
 	// for test
@@ -84,13 +96,14 @@ public class Code04_IsFull {
 		int maxLevel = 5;
 		int maxValue = 100;
 		int testTimes = 1000000;
+		System.out.println("测试开始");
 		for (int i = 0; i < testTimes; i++) {
 			Node head = generateRandomBST(maxLevel, maxValue);
 			if (isFull1(head) != isFull2(head)) {
-				System.out.println("Oops!");
+				System.out.println("出错了!");
 			}
 		}
-		System.out.println("finish!");
+		System.out.println("测试结束");
 	}
 
 }