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gitsunmin.ts
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34 lines (27 loc) · 868 Bytes
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/**
* https://leetcode.com/problems/invert-binary-tree/
* time complexity : O(n)
* space complexity : O(log N)
*/
class TreeNode {
val: number
left: TreeNode | null
right: TreeNode | null
constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
this.val = (val === undefined ? 0 : val)
this.left = (left === undefined ? null : left)
this.right = (right === undefined ? null : right)
}
}
export const dfs = (root: TreeNode | null, inverted: TreeNode | null): TreeNode | null => {
if (!root) return null;
const left = dfs(root.left, inverted);
const right = dfs(root.right, inverted);
root.left = right;
root.right = left;
return root;
};
function invertTree(root: TreeNode | null): TreeNode | null {
if (!root) return null;
return dfs(root, new TreeNode(0));
};