力扣530题(二叉搜索树的最小绝对差)
作者:互联网
530、二叉搜索树的最小绝对差
基本思想:
中序遍历
具体实现:
代码:
class Solution { TreeNode pre;//记录上一个遍历的节点 int result = Integer.MAX_VALUE; public int getMinimumDifference(TreeNode root) { if (root == null) return 0 ; traversal(root); return result; } public void traversal(TreeNode root){ if (root == null) return; traversal(root.left); if (pre != null) result = Math.min(result, root.val - pre.val); pre = root; traversal(root.right); } }
迭代法:
class Solution { TreeNode pre; Stack<TreeNode> stack; public int getMinimumDifference(TreeNode root) { if (root == null) return 0; stack = new Stack<>(); TreeNode cur = root; int result = Integer.MAX_VALUE; while (cur != null || !stack.isEmpty()) { if (cur != null) { stack.push(cur); // 将访问的节点放进栈 cur = cur.left; // 左 }else { cur = stack.pop(); if (pre != null) { // 中 result = Math.min(result, cur.val - pre.val); } pre = cur; cur = cur.right; // 右 } } return result; } }
标签:pre,TreeNode,cur,二叉,力扣,result,530,null,root 来源: https://www.cnblogs.com/zhaojiayu/p/15564262.html