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feat: add problem minimum-flips-in-binary-tree-to-get-result with unit tests (#77)
closes #76
1 parent a835dd9 commit be89904

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‎README.md‎

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@@ -164,18 +164,20 @@ This repository covers a comprehensive range of algorithmic patterns and data st
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- [Two Pointers](#two-pointers)
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- [Sliding Window](#sliding-window)
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- [Stack](#stack)
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- [Matrix](#matrix)
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- [Intervals](#intervals)
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- [Binary Search](#binary-search)
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- [Linked List](#linked-list)
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- [Binary Tree General](#binary-tree-general)
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- [Binary Tree BFS](#binary-tree-bfs)
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- [Binary Search Tree](#binary-search-tree)
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- [Graph General](#graph-general)
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- [Dynamic Programming](#dynamic-programming)
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- [Trees](#trees)
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- [Heap / Priority Queue](#heap-/-priority-queue)
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- [Backtracking](#backtracking)
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- [Heap](#heap)
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- [Tries](#tries)
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- [Graphs](#graphs)
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- [Advanced Graphs](#advanced-graphs)
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- [1-D Dynamic Programming](#1-d-dynamic-programming)
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- [2-D Dynamic Programming](#2-d-dynamic-programming)
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- [Greedy](#greedy)
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- [Trie](#trie)
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- [Intervals](#intervals)
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- [Math & Geometry](#math--geometry)
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- [Bit Manipulation](#bit-manipulation)
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## Arrays & Hashing
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| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
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|---|-------|----------|------|-------|------------|-----|------|
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| 125 | [Valid Palindrome](https://leetcode.com/problems/valid-palindrome/) | [Python](./problems/valid_palindrome/valid_palindrome.py), [C++](./problems/valid_palindrome/valid_palindrome.cc) | _O(n)_ | _O(1)_ | Easy | | |
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## Trees
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| # | Title | Solution | Time | Space | Difficulty | Tag | Note |
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|---|-------|----------|------|-------|------------|-----|------|
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| 2313 | [Minimum Flips in Binary Tree to Get Result](https://leetcode.com/problems/minimum-flips-in-binary-tree-to-get-result/description/) | [Python](./problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.py), [C++](./problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.cc) | _O(n)_ | _O(1)_ | Hard | | _n_ is the number of nodes in the binary tree. |

‎common/.gitkeep‎

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‎common/__init__.py‎

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from .trees.treenode import TreeNode
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__all__ = ["TreeNode"]

‎common/trees/treenode.h‎

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#ifndef COMMON_TREES_TREENODE_H
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#define COMMON_TREES_TREENODE_H
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// Definition for a binary tree node.
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struct TreeNode {
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int val;
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TreeNode *left;
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TreeNode *right;
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TreeNode() : val(0), left(nullptr), right(nullptr) {}
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TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
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TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
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};
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#endif // COMMON_TREES_TREENODE_H

‎common/trees/treenode.py‎

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"""Common tree node definition."""
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# Definition for a binary tree node.
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class TreeNode:
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def __init__(self, val=0, left=None, right=None):
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self.val = val
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self.left = left
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self.right = right

‎config/tags.yml‎

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- "Two Pointers"
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- "Sliding Window"
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- "Stack"
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- "Matrix"
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- "Intervals"
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- "Binary Search"
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- "Linked List"
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- "Binary Tree General"
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- "Binary Tree BFS"
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- "Binary Search Tree"
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- "Graph General"
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- "Dynamic Programming"
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- "Trees"
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- "Heap / Priority Queue"
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- "Backtracking"
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- "Heap"
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- "Tries"
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- "Graphs"
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- "Advanced Graphs"
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- "1-D Dynamic Programming"
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- "2-D Dynamic Programming"
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- "Greedy"
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- "Trie"
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- "Intervals"
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- "Math & Geometry"
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- "Bit Manipulation"

‎problems/minimum_flips_in_binary_tree_to_get_result/config.yml‎

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problem:
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number: 2313
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title: "Minimum Flips in Binary Tree to Get Result"
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leetcode_url: "https://leetcode.com/problems/minimum-flips-in-binary-tree-to-get-result/description/"
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difficulty: "hard"
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tags: ["Trees"]
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solutions:
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python: "problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.py"
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cpp: "problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.cc"
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complexity:
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time: "O(n)"
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space: "O(1)"
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notes: "_n_ is the number of nodes in the binary tree."
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readme_link: ""

‎problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.cc‎

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#include "minimum_flips_in_binary_tree_to_get_result.h"
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#include <algorithm>
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#include <functional>
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#include <utility>
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#include "../../common/trees/treenode.h"
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using namespace std;
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int minimumFlips(TreeNode* root, bool result) {
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function<pair<int, int>(TreeNode*)> dfs = [&](TreeNode* node) -> pair<int, int> {
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if (!node) {
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return {1 << 30, 1 << 30}; // Impossible case
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}
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const int x = node->val;
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if (x >= 0 && x <= 1) {
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return {x == 0 ? 0 : 1, x == 1 ? 0 : 1};
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}
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auto [left_false, left_true] = dfs(node->left);
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auto [right_false, right_true] = dfs(node->right);
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if (x == 2) { // OR
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return {left_false + right_false, min({left_true + right_true, left_true + right_false,
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left_false + right_true})};
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} else if (x == 3) { // AND
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return {
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min({left_false + right_false, left_true + right_false, left_false + right_true}),
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left_true + right_true};
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} else if (x == 4) { // XOR
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return {min({left_false + right_false, left_true + right_true}),
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min({left_true + right_false, left_false + right_true})};
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} else if (x == 5) { // NOT
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return {left_true, left_false};
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} else {
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return {1 << 30, 1 << 30}; // Invalid operation
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}
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};
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return result ? dfs(root).second : dfs(root).first;
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}

‎problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.h‎

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#include "../../common/trees/treenode.h"
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int minimumFlips(TreeNode* root, bool result);

‎problems/minimum_flips_in_binary_tree_to_get_result/minimum_flips_in_binary_tree_to_get_result.py‎

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from common import TreeNode
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from math import inf
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from typing import Optional, Tuple
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def minimumFlips(root: Optional[TreeNode], result: bool) -> int:
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def dfs(node: Optional[TreeNode]) -> Tuple[int, int]:
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"""Returns a tuple (min_flips_to_false, min_flips_to_true)"""
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if node is None:
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return inf, inf
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x = node.val
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if x in (0, 1):
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return (1, 0) if x == 1 else (0, 1)
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left_false, left_true = dfs(node.left)
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right_false, right_true = dfs(node.right)
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if x == 2: # OR
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return (
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left_false + right_false,
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min(
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left_true + right_false,
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left_false + right_true,
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left_true + right_true,
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),
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)
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elif x == 3: # AND
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return (
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min(
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left_false + right_false,
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left_false + right_true,
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left_true + right_false,
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),
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left_true + right_true,
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)
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elif x == 4: # XOR
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return (
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min(left_false + right_false, left_true + right_true),
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min(left_false + right_true, left_true + right_false),
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)
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elif x == 5: # NOT
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return (left_true, left_false)
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else:
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raise ValueError(f"Unknown operation: {x}")
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return dfs(root)[int(result)]

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