modify code

src/class12/Code05_MaxSubBSTSize.java

@@ -1,154 +1,24 @@
 package class12;
 
-import java.util.ArrayList;
-
+// 在线测试链接 : https://leetcode.com/problems/largest-bst-subtree
 public class Code05_MaxSubBSTSize {
 
-	public static class Node {
-		public int value;
-		public Node left;
-		public Node right;
-
-		public Node(int data) {
-			this.value = data;
-		}
-	}
-
-	public static int getBSTSize(Node head) {
-		if (head == null) {
-			return 0;
-		}
-		ArrayList<Node> arr = new ArrayList<>();
-		in(head, arr);
-		for (int i = 1; i < arr.size(); i++) {
-			if (arr.get(i).value <= arr.get(i - 1).value) {
-				return 0;
-			}
-		}
-		return arr.size();
-	}
+	// 提交时不要提交这个类
+	public static class TreeNode {
+		public int val;
+		public TreeNode left;
+		public TreeNode right;
 
-	public static void in(Node head, ArrayList<Node> arr) {
-		if (head == null) {
-			return;
+		public TreeNode(int value) {
+			val = value;
 		}
-		in(head.left, arr);
-		arr.add(head);
-		in(head.right, arr);
 	}
 
-	public static int maxSubBSTSize1(Node head) {
+	// 提交如下的代码，可以直接通过
+	public static int largestBSTSubtree(TreeNode head) {
 		if (head == null) {
 			return 0;
 		}
-		int h = getBSTSize(head);
-		if (h != 0) {
-			return h;
-		}
-		return Math.max(maxSubBSTSize1(head.left), maxSubBSTSize1(head.right));
-	}
-
-//	public static int maxSubBSTSize2(Node head) {
-//		if (head == null) {
-//			return 0;
-//		}
-//		return process(head).maxSubBSTSize;
-//	}
-//	
-//	
-//	
-//	
-//	
-//	
-//	
-//	
-//	
-//	// 任何子树
-//	public static class Info {
-//		public boolean isAllBST;
-//		public int maxSubBSTSize;
-//		public int min;
-//		public int max;
-//
-//		public Info(boolean is, int size, int mi, int ma) {
-//			isAllBST = is;
-//			maxSubBSTSize = size;
-//			min = mi;
-//			max = ma;
-//		}
-//	}
-//	
-//	
-//	
-//	
-//	public static Info process(Node X) {
-//		if(X == null) {
-//			return null;
-//		}
-//		Info leftInfo = process(X.left);
-//		Info rightInfo = process(X.right);
-//		
-//		
-//		
-//		int min = X.value;
-//		int max = X.value;
-//		
-//		if(leftInfo != null) {
-//			min = Math.min(min, leftInfo.min);
-//			max = Math.max(max, leftInfo.max);
-//		}
-//		if(rightInfo != null) {
-//			min = Math.min(min, rightInfo.min);
-//			max = Math.max(max, rightInfo.max);
-//		}
-//		
-//		
-//		
-//		
-//		
-//		
-//
-//		int maxSubBSTSize = 0;
-//		if(leftInfo != null) {
-//			maxSubBSTSize = leftInfo.maxSubBSTSize;
-//		}
-//		if(rightInfo !=null) {
-//			maxSubBSTSize = Math.max(maxSubBSTSize, rightInfo.maxSubBSTSize);
-//		}
-//		boolean isAllBST = false;
-//		
-//		
-//		if(
-//				// 左树整体需要是搜索二叉树
-//				(  leftInfo == null ? true : leftInfo.isAllBST    )
-//				&&
-//				(  rightInfo == null ? true : rightInfo.isAllBST    )
-//				&&
-//				// 左树最大值<x
-//				(leftInfo == null ? true : leftInfo.max < X.value)
-//				&&
-//				(rightInfo == null ? true : rightInfo.min > X.value)
-//				
-//				
-//				) {
-//			
-//			maxSubBSTSize = 
-//					(leftInfo == null ? 0 : leftInfo.maxSubBSTSize)
-//					+
-//					(rightInfo == null ? 0 : rightInfo.maxSubBSTSize)
-//					+
-//					1;
-//					isAllBST = true;
-//			
-//			
-//		}
-//		return new Info(isAllBST, maxSubBSTSize, min, max);
-//	}
-
-	public static int maxSubBSTSize2(Node head) {
-		if(head == null) {
-			return 0;
-		}
 		return process(head).maxBSTSubtreeSize;
 	}
 
@@ -166,14 +36,14 @@ public class Code05_MaxSubBSTSize {
 		}
 	}
 
-	public static Info process(Node x) {
+	public static Info process(TreeNode x) {
 		if (x == null) {
 			return null;
 		}
 		Info leftInfo = process(x.left);
 		Info rightInfo = process(x.right);
-		int max = x.value;
-		int min = x.value;
+		int max = x.val;
+		int min = x.val;
 		int allSize = 1;
 		if (leftInfo != null) {
 			max = Math.max(leftInfo.max, max);
@@ -197,8 +67,8 @@ public class Code05_MaxSubBSTSize {
 		boolean leftBST = leftInfo == null ? true : (leftInfo.maxBSTSubtreeSize == leftInfo.allSize);
 		boolean rightBST = rightInfo == null ? true : (rightInfo.maxBSTSubtreeSize == rightInfo.allSize);
 		if (leftBST && rightBST) {
-			boolean leftMaxLessX = leftInfo == null ? true : (leftInfo.max < x.value);
-			boolean rightMinMoreX = rightInfo == null ? true : (x.value < rightInfo.min);
+			boolean leftMaxLessX = leftInfo == null ? true : (leftInfo.max < x.val);
+			boolean rightMinMoreX = rightInfo == null ? true : (x.val < rightInfo.min);
 			if (leftMaxLessX && rightMinMoreX) {
 				int leftSize = leftInfo == null ? 0 : leftInfo.allSize;
 				int rightSize = rightInfo == null ? 0 : rightInfo.allSize;
@@ -208,33 +78,4 @@ public class Code05_MaxSubBSTSize {
 		return new Info(Math.max(p1, Math.max(p2, p3)), allSize, max, min);
 	}
 
-	// for test
-	public static Node generateRandomBST(int maxLevel, int maxValue) {
-		return generate(1, maxLevel, maxValue);
-	}
-
-	// for test
-	public static Node generate(int level, int maxLevel, int maxValue) {
-		if (level > maxLevel || Math.random() < 0.5) {
-			return null;
-		}
-		Node head = new Node((int) (Math.random() * maxValue));
-		head.left = generate(level + 1, maxLevel, maxValue);
-		head.right = generate(level + 1, maxLevel, maxValue);
-		return head;
-	}
-
-	public static void main(String[] args) {
-		int maxLevel = 4;
-		int maxValue = 100;
-		int testTimes = 1000000;
-		for (int i = 0; i < testTimes; i++) {
-			Node head = generateRandomBST(maxLevel, maxValue);
-			if (maxSubBSTSize1(head) != maxSubBSTSize2(head)) {
-				System.out.println("Oops!");
-			}
-		}
-		System.out.println("finish!");
-	}
-
 }