今天小编给大家分享一下Java二叉树的构造和遍历方法是什么的相关知识点，内容详细，逻辑清晰，相信大部分人都还太了解这方面的知识，所以分享这篇文章给大家参考一下，希望大家阅读完这篇文章后有所收获，下面我们一起来了解一下吧。
题目一
解法
class Solution { public TreeNode constructMaximumBinaryTree(int[] nums) { return method(nums,0,nums.length-1); } public TreeNode method(int[] nums,int lo,int hi){ if(lo>hi){ return null; } int index = -1; int max = Integer.MIN_VALUE; for(int i = lo;i<=hi;i++){ if(max<nums[i]){ max = nums[i]; index = i; } } TreeNode root = new TreeNode(max); root.left = method(nums,lo,index-1); root.right = method(nums,index+1,hi); return root; }}题目二
解法
class Solution { public TreeNode buildTree(int[] preorder, int[] inorder) { return method(preorder,0,preorder.length-1,inorder,0,inorder.length-1); } public TreeNode method(int[] preorder, int preLeft,int preEnd , int[] inorder,int inLeft,int inEnd){ if(preLeft>preEnd){ return null; } int rootVal = preorder[preLeft]; int index = -1; for(int i = inLeft;i<=inEnd;i++){ if(rootVal == inorder[i]){ index = i; } } TreeNode root = new TreeNode(rootVal); int leftSize = index - inLeft; root.left = method(preorder,preLeft+1,leftSize+preLeft,inorder,inLeft,index-1); root.right = method(preorder,leftSize+preLeft+1,preEnd,inorder,index+1,inEnd); return root; }}题目三
解法
class Solution { public TreeNode buildTree(int[] inorder, int[] postorder) { return build(inorder,0,inorder.length-1,postorder,0,postorder.length-1); } TreeNode build(int[] inorder, int inStart, int inEnd,int[] postorder, int postStart, int postEnd) { if (inStart > inEnd) { return null; } // root 节点对应的值就是后序遍历数组的最后一个元素 int rootVal = postorder[postEnd]; // rootVal 在中序遍历数组中的索引 int index = 0; for (int i = inStart; i <= inEnd; i++) { if (inorder[i] == rootVal) { index = i; break; } } // 左子树的节点个数 int leftSize = index - inStart; TreeNode root = new TreeNode(rootVal); // 递归构造左右子树 root.left = build(inorder, inStart, index - 1,postorder, postStart, postStart + leftSize - 1); root.right = build(inorder, index + 1, inEnd,postorder, postStart + leftSize, postEnd - 1); return root;}}题目四
解法
class Solution { public TreeNode constructFromPrePost(int[] preorder, int[] postorder) { return method(preorder,0,preorder.length-1,postorder,0,postorder.length-1); } public TreeNode method(int[] preorder,int preStart, int preEnd, int[] postorder,int postStart,int postEnd){ if(preStart>preEnd){ return null; } if(preStart==preEnd){ return new TreeNode(preorder[preStart]); } int rootVal = preorder[preStart]; int leftRootVal = preorder[preStart + 1]; int index = 0; for (int i = postStart; i < postEnd; i++) { if (postorder[i] == leftRootVal) { index = i; break; } } TreeNode root = new TreeNode(rootVal); int leftSize = index - postStart + 1; root.left = method(preorder, preStart + 1, preStart + leftSize,postorder, postStart, index); root.right = method(preorder, preStart + leftSize + 1, preEnd,postorder, index + 1, postEnd - 1); return root; }}以上就是“Java二叉树的构造和遍历方法是什么”这篇文章的所有内容，感谢各位的阅读！相信大家阅读完这篇文章都有很大的收获，小编每天都会为大家更新不同的知识，如果还想学习更多的知识，请关注编程网行业资讯频道。
