From 909f08fac65e2b402b3e157175bcaa5f02ecab73 Mon Sep 17 00:00:00 2001
From: byol-han <byolhandev@gmail.com>
Date: Sun, 22 Jun 2025 21:08:53 -0700
Subject: [PATCH 1/4] meeting rooms solution

---
 meeting-rooms/byol-han.js | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 meeting-rooms/byol-han.js

diff --git a/meeting-rooms/byol-han.js b/meeting-rooms/byol-han.js
new file mode 100644
index 000000000..c125a7723
--- /dev/null
+++ b/meeting-rooms/byol-han.js
@@ -0,0 +1,37 @@
+import { Interval } from '/opt/node/lib/lintcode/index.js';
+
+/**
+ * https://www.lintcode.com/problem/920/
+ * Definition of Interval:
+ * class Interval {
+ *   constructor(start, end) {
+ *     this.start = start;
+ *     this.end = end;
+ *   }
+ * }
+ */
+
+export class Solution {
+  /**
+   * @param intervals: an array of meeting time intervals
+   * @return: if a person could attend all meetings
+   */
+  canAttendMeetings(intervals) {
+    // 먼저 회의를 시작 시간 기준으로 정렬합니다.
+    intervals.sort((a, b) => a[0] - b[0]);
+
+    // 정렬된 회의들을 순차적으로 비교하며 겹치는지 확인합니다.
+    for (let i = 1; i < intervals.length; i++) {
+      const prevEnd = intervals[i - 1][1]; // 이전 회의의 끝 시간
+      const currStart = intervals[i][0]; // 현재 회의의 시작 시간
+
+      // 이전 회의의 끝 시간보다 현재 회의의 시작 시간이 빠르면 겹칩니다.
+      if (currStart < prevEnd) {
+        return false;
+      }
+    }
+
+    // 겹치는 회의가 없으면 true를 반환합니다.
+    return true;
+  }
+}

From 1cb8871ee1959cdee9d9340b354954e95d7e6b90 Mon Sep 17 00:00:00 2001
From: byol-han <byolhandev@gmail.com>
Date: Fri, 27 Jun 2025 02:44:09 -0700
Subject: [PATCH 2/4] lowest-common-ancestor-of-a-binary-search-tree solution

---
 .../byol-han.js                               | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 lowest-common-ancestor-of-a-binary-search-tree/byol-han.js

diff --git a/lowest-common-ancestor-of-a-binary-search-tree/byol-han.js b/lowest-common-ancestor-of-a-binary-search-tree/byol-han.js
new file mode 100644
index 000000000..3667cf122
--- /dev/null
+++ b/lowest-common-ancestor-of-a-binary-search-tree/byol-han.js
@@ -0,0 +1,35 @@
+/**
+ * https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+
+/**
+ * @param {TreeNode} root
+ * @param {TreeNode} p
+ * @param {TreeNode} q
+ * @return {TreeNode}
+ */
+var lowestCommonAncestor = function (root, p, q) {
+  let current = root;
+
+  while (current) {
+    // 두 노드의 값이 현재 노드보다 모두 작으면 왼쪽 서브트리로 이동
+    if (p.val < current.val && q.val < current.val) {
+      current = current.left;
+    }
+    // 두 노드의 값이 현재 노드보다 모두 크면 오른쪽 서브트리로 이동
+    else if (p.val > current.val && q.val > current.val) {
+      current = current.right;
+    }
+    // 현재 노드가 분기점이면 그게 LCA!
+    else {
+      return current;
+    }
+  }
+
+  return null; // 만약 트리에 없다면 null 반환 (일반적으로 BST에는 항상 존재한다고 가정)
+};

From b254839d28cc894a43a94911b585098793edfcaf Mon Sep 17 00:00:00 2001
From: byol-han <byolhandev@gmail.com>
Date: Fri, 27 Jun 2025 02:47:29 -0700
Subject: [PATCH 3/4] kth-smallest-element-in-a-bst

---
 kth-smallest-element-in-a-bst/byol-han.js | 32 +++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 kth-smallest-element-in-a-bst/byol-han.js

diff --git a/kth-smallest-element-in-a-bst/byol-han.js b/kth-smallest-element-in-a-bst/byol-han.js
new file mode 100644
index 000000000..50ff0bcfa
--- /dev/null
+++ b/kth-smallest-element-in-a-bst/byol-han.js
@@ -0,0 +1,32 @@
+/**
+ * https://leetcode.com/problems/kth-smallest-element-in-a-bst/
+ * 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
+ * @param {number} k
+ * @return {number}
+ */
+var kthSmallest = function (root, k) {
+  // 중위 순회 결과를 저장할 배열
+  const inorder = [];
+
+  // 중위 순회 함수 정의
+  function traverse(node) {
+    if (!node) return;
+    traverse(node.left); // 왼쪽 서브트리 방문
+    inorder.push(node.val); // 현재 노드 값 추가
+    traverse(node.right); // 오른쪽 서브트리 방문
+  }
+
+  // 트리 순회 시작
+  traverse(root);
+
+  // k번째로 작은 값 반환 (1-indexed 이므로 k-1)
+  return inorder[k - 1];
+};

From fbcc68af7019ddd150832c8dc909be4acbbb9c2b Mon Sep 17 00:00:00 2001
From: byol-han <byolhandev@gmail.com>
Date: Fri, 27 Jun 2025 02:49:48 -0700
Subject: [PATCH 4/4] insert-interval solution

---
 insert-interval/byol-han.js | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 insert-interval/byol-han.js

diff --git a/insert-interval/byol-han.js b/insert-interval/byol-han.js
new file mode 100644
index 000000000..6d7a5ccd5
--- /dev/null
+++ b/insert-interval/byol-han.js
@@ -0,0 +1,33 @@
+/**
+ * https://leetcode.com/problems/insert-interval/submissions/1678158074/
+ * @param {number[][]} intervals
+ * @param {number[]} newInterval
+ * @return {number[][]}
+ */
+var insert = function (intervals, newInterval) {
+  const result = [];
+  let i = 0;
+  const n = intervals.length;
+
+  // 1. newInterval보다 끝나는 시점이 먼저인 interval은 그냥 추가
+  while (i < n && intervals[i][1] < newInterval[0]) {
+    result.push(intervals[i]);
+    i++;
+  }
+
+  // 2. newInterval과 겹치는 interval은 병합
+  while (i < n && intervals[i][0] <= newInterval[1]) {
+    newInterval[0] = Math.min(newInterval[0], intervals[i][0]);
+    newInterval[1] = Math.max(newInterval[1], intervals[i][1]);
+    i++;
+  }
+  result.push(newInterval);
+
+  // 3. 나머지 interval은 그대로 추가
+  while (i < n) {
+    result.push(intervals[i]);
+    i++;
+  }
+
+  return result;
+};