From 543425a3c31d6a08fc1f761193a8b3a76fc91cb2 Mon Sep 17 00:00:00 2001
From: ganu <gwbaik9717@icloud.com>
Date: Wed, 12 Mar 2025 09:01:26 +0900
Subject: [PATCH 1/5] feat: house-rober-ii
---
house-robber-ii/gwbaik9717.js | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644 house-robber-ii/gwbaik9717.js
diff --git a/house-robber-ii/gwbaik9717.js b/house-robber-ii/gwbaik9717.js
new file mode 100644
index 000000000..12b069294
--- /dev/null
+++ b/house-robber-ii/gwbaik9717.js
@@ -0,0 +1,26 @@
+// Time complexity: O(n)
+// Space complexity: O(n)
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var rob = function (nums) {
+ if (nums.length === 1) {
+ return nums[0];
+ }
+
+ // include first
+ const dp1 = Array.from({ length: nums.length + 1 }, () => 0);
+ dp1[1] = nums[0];
+
+ // exclude first
+ const dp2 = Array.from({ length: nums.length + 1 }, () => 0);
+
+ for (let i = 2; i <= nums.length; i++) {
+ dp1[i] = Math.max(dp1[i - 2] + nums[i - 1], dp1[i - 1]);
+ dp2[i] = Math.max(dp2[i - 2] + nums[i - 1], dp2[i - 1]);
+ }
+
+ return Math.max(dp1.at(-2), dp2.at(-1));
+};
From 319ece1db4d08fb1d6d4a0b938d9a03db241be27 Mon Sep 17 00:00:00 2001
From: ganu <gwbaik9717@icloud.com>
Date: Thu, 13 Mar 2025 09:04:13 +0900
Subject: [PATCH 2/5] feat: word-search-ii
---
word-search-ii/gwbaik9717.js | 79 ++++++++++++++++++++++++++++++++++++
1 file changed, 79 insertions(+)
create mode 100644 word-search-ii/gwbaik9717.js
diff --git a/word-search-ii/gwbaik9717.js b/word-search-ii/gwbaik9717.js
new file mode 100644
index 000000000..0ff3a15f2
--- /dev/null
+++ b/word-search-ii/gwbaik9717.js
@@ -0,0 +1,79 @@
+// n: length of words, k: length of word, h: height of board, w: width of board
+// Time complexity: O(4^k * h * w * n)
+// Space complexity: O(4^k)
+
+/**
+ * @param {character[][]} board
+ * @param {string[]} words
+ * @return {string[]}
+ */
+var findWords = function (board, words) {
+ const h = board.length;
+ const w = board[0].length;
+
+ const dy = [1, 0, -1, 0];
+ const dx = [0, 1, 0, -1];
+ const checked = Array.from({ length: h }, () =>
+ Array.from({ length: w }, () => false)
+ );
+
+ const findWord = (current, i, word) => {
+ const [cy, cx] = current;
+
+ if (i === word.length - 1) {
+ return true;
+ }
+
+ let found = false;
+
+ for (let j = 0; j < dx.length; j++) {
+ const nx = cx + dx[j];
+ const ny = cy + dy[j];
+
+ if (nx >= 0 && nx < w && ny >= 0 && ny < h && !checked[ny][nx]) {
+ if (board[ny][nx] === word[i + 1]) {
+ checked[ny][nx] = true;
+
+ if (findWord([ny, nx], i + 1, word)) {
+ found = true;
+ }
+
+ checked[ny][nx] = false;
+ }
+ }
+ }
+
+ return found;
+ };
+
+ const answer = [];
+
+ for (const word of words) {
+ let found = false;
+
+ for (let i = 0; i < h; i++) {
+ if (found) {
+ break;
+ }
+
+ for (let j = 0; j < w; j++) {
+ if (found) {
+ break;
+ }
+
+ if (board[i][j] === word[0]) {
+ checked[i][j] = true;
+
+ if (findWord([i, j], 0, word)) {
+ answer.push(word);
+ found = true;
+ }
+
+ checked[i][j] = false;
+ }
+ }
+ }
+ }
+
+ return answer;
+};
From 100154c7ae4cb1cc9ae6d261548882a25619a04f Mon Sep 17 00:00:00 2001
From: ganu <gwbaik9717@icloud.com>
Date: Fri, 14 Mar 2025 09:37:45 +0900
Subject: [PATCH 3/5] refactor: word-search-ii
---
word-search-ii/gwbaik9717.js | 90 ++++++++++++++++++++----------------
1 file changed, 49 insertions(+), 41 deletions(-)
diff --git a/word-search-ii/gwbaik9717.js b/word-search-ii/gwbaik9717.js
index 0ff3a15f2..bdc5217d1 100644
--- a/word-search-ii/gwbaik9717.js
+++ b/word-search-ii/gwbaik9717.js
@@ -1,13 +1,42 @@
-// n: length of words, k: length of word, h: height of board, w: width of board
-// Time complexity: O(4^k * h * w * n)
+// k: length of word, h: height of board, w: width of board
+// Time complexity: O(4^k * h * w)
// Space complexity: O(4^k)
+class Node {
+ constructor(value = "") {
+ this.value = value;
+ this.children = new Map();
+ this.isEnd = false;
+ }
+}
+class Trie {
+ constructor() {
+ this.head = new Node();
+ }
+
+ add(str) {
+ let current = this.head;
+
+ for (const chr of str) {
+ if (!current.children.has(chr)) {
+ current.children.set(chr, new Node(current.value + chr));
+ }
+
+ current = current.children.get(chr);
+ }
+
+ current.isEnd = true;
+ }
+}
+
/**
* @param {character[][]} board
* @param {string[]} words
* @return {string[]}
*/
var findWords = function (board, words) {
+ const answer = new Set();
+
const h = board.length;
const w = board[0].length;
@@ -17,63 +46,42 @@ var findWords = function (board, words) {
Array.from({ length: w }, () => false)
);
- const findWord = (current, i, word) => {
+ const dfs = (current, children) => {
const [cy, cx] = current;
- if (i === word.length - 1) {
- return true;
+ if (!children.has(board[cy][cx])) {
+ return;
}
- let found = false;
+ if (children.get(board[cy][cx]).isEnd) {
+ answer.add(children.get(board[cy][cx]).value);
+ }
for (let j = 0; j < dx.length; j++) {
const nx = cx + dx[j];
const ny = cy + dy[j];
if (nx >= 0 && nx < w && ny >= 0 && ny < h && !checked[ny][nx]) {
- if (board[ny][nx] === word[i + 1]) {
- checked[ny][nx] = true;
-
- if (findWord([ny, nx], i + 1, word)) {
- found = true;
- }
-
- checked[ny][nx] = false;
- }
+ checked[ny][nx] = true;
+ dfs([ny, nx], children.get(board[cy][cx]).children);
+ checked[ny][nx] = false;
}
}
-
- return found;
};
- const answer = [];
+ const trie = new Trie();
for (const word of words) {
- let found = false;
-
- for (let i = 0; i < h; i++) {
- if (found) {
- break;
- }
-
- for (let j = 0; j < w; j++) {
- if (found) {
- break;
- }
-
- if (board[i][j] === word[0]) {
- checked[i][j] = true;
-
- if (findWord([i, j], 0, word)) {
- answer.push(word);
- found = true;
- }
+ trie.add(word);
+ }
- checked[i][j] = false;
- }
- }
+ for (let i = 0; i < h; i++) {
+ for (let j = 0; j < w; j++) {
+ checked[i][j] = true;
+ dfs([i, j], trie.head.children);
+ checked[i][j] = false;
}
}
- return answer;
+ return [...answer];
};
From f5b7405f69a34b0a22a71a98138ac56be1967f37 Mon Sep 17 00:00:00 2001
From: ganu <gwbaik9717@icloud.com>
Date: Sat, 15 Mar 2025 10:20:39 +0900
Subject: [PATCH 4/5] feat: Binary Tree Level Order Traversal
---
.../gwbaik9717.js | 67 +++++++++++++++++++
1 file changed, 67 insertions(+)
create mode 100644 binary-tree-level-order-traversal/gwbaik9717.js
diff --git a/binary-tree-level-order-traversal/gwbaik9717.js b/binary-tree-level-order-traversal/gwbaik9717.js
new file mode 100644
index 000000000..4bfc40282
--- /dev/null
+++ b/binary-tree-level-order-traversal/gwbaik9717.js
@@ -0,0 +1,67 @@
+// n: number of nodes
+// Time complexity: O(n)
+// Space complexity: O(n)
+
+class _Queue {
+ constructor() {
+ this.q = [];
+ this.front = 0;
+ this.rear = 0;
+ }
+
+ push(value) {
+ this.q.push(value);
+ this.rear++;
+ }
+
+ shift() {
+ const rv = this.q[this.front];
+ delete this.q[this.front++];
+ return rv;
+ }
+
+ isEmpty() {
+ return this.front === this.rear;
+ }
+}
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ * this.val = (val===undefined ? 0 : val)
+ * this.left = (left===undefined ? null : left)
+ * this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number[][]}
+ */
+var levelOrder = function (root) {
+ const answer = [];
+ const q = new _Queue();
+
+ if (root) {
+ q.push([root, 0]);
+ }
+
+ while (!q.isEmpty()) {
+ const [current, lv] = q.shift();
+
+ if (answer.at(lv) === undefined) {
+ answer[lv] = [];
+ }
+
+ answer[lv].push(current.val);
+
+ if (current.left) {
+ q.push([current.left, lv + 1]);
+ }
+
+ if (current.right) {
+ q.push([current.right, lv + 1]);
+ }
+ }
+
+ return answer;
+};
From cec6d454628437b6dda871389c2f3ba2616a56c8 Mon Sep 17 00:00:00 2001
From: ganu <gwbaik9717@icloud.com>
Date: Sat, 15 Mar 2025 10:54:14 +0900
Subject: [PATCH 5/5] feat: counting bits
---
counting-bits/gwbaik9717.js | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
create mode 100644 counting-bits/gwbaik9717.js
diff --git a/counting-bits/gwbaik9717.js b/counting-bits/gwbaik9717.js
new file mode 100644
index 000000000..6a8681031
--- /dev/null
+++ b/counting-bits/gwbaik9717.js
@@ -0,0 +1,24 @@
+// Time complexity: O(n)
+// Space complexity: O(n)
+
+/**
+ * @param {number} n
+ * @return {number[]}
+ */
+var countBits = function (n) {
+ const dp = Array.from({ length: n + 1 }, () => 0);
+
+ if (n === 0) {
+ return dp;
+ }
+
+ dp[1] = 1;
+
+ for (let i = 2; i <= n; i++) {
+ const k = Math.floor(Math.log2(i));
+
+ dp[i] = 1 + dp[i - Math.pow(2, k)];
+ }
+
+ return dp;
+};