diff --git a/problems/0101.对称二叉树.md b/problems/0101.对称二叉树.md index 69bc41d3..e4e232c8 100644 --- a/problems/0101.对称二叉树.md +++ b/problems/0101.对称二叉树.md @@ -574,6 +574,75 @@ var isSymmetric = function(root) { }; ``` +## TypeScript: + +> 递归法 + +```typescript +function isSymmetric(root: TreeNode | null): boolean { + function recur(node1: TreeNode | null, node2: TreeNode | null): boolean { + if (node1 === null && node2 === null) return true; + if (node1 === null || node2 === null) return false; + if (node1.val !== node2.val) return false + let isSym1: boolean = recur(node1.left, node2.right); + let isSym2: boolean = recur(node1.right, node2.left); + return isSym1 && isSym2 + } + if (root === null) return true; + return recur(root.left, root.right); +}; +``` + +> 迭代法 + +```typescript +// 迭代法(队列) +function isSymmetric(root: TreeNode | null): boolean { + let helperQueue: (TreeNode | null)[] = []; + let tempNode1: TreeNode | null, + tempNode2: TreeNode | null; + if (root !== null) { + helperQueue.push(root.left); + helperQueue.push(root.right); + } + while (helperQueue.length > 0) { + tempNode1 = helperQueue.shift()!; + tempNode2 = helperQueue.shift()!; + if (tempNode1 === null && tempNode2 === null) continue; + if (tempNode1 === null || tempNode2 === null) return false; + if (tempNode1.val !== tempNode2.val) return false; + helperQueue.push(tempNode1.left); + helperQueue.push(tempNode2.right); + helperQueue.push(tempNode1.right); + helperQueue.push(tempNode2.left); + } + return true; +} + +// 迭代法(栈) +function isSymmetric(root: TreeNode | null): boolean { + let helperStack: (TreeNode | null)[] = []; + let tempNode1: TreeNode | null, + tempNode2: TreeNode | null; + if (root !== null) { + helperStack.push(root.left); + helperStack.push(root.right); + } + while (helperStack.length > 0) { + tempNode1 = helperStack.pop()!; + tempNode2 = helperStack.pop()!; + if (tempNode1 === null && tempNode2 === null) continue; + if (tempNode1 === null || tempNode2 === null) return false; + if (tempNode1.val !== tempNode2.val) return false; + helperStack.push(tempNode1.left); + helperStack.push(tempNode2.right); + helperStack.push(tempNode1.right); + helperStack.push(tempNode2.left); + } + return true; +}; +``` + ## Swift: > 递归