From d6e47fe6922b5c39ca6e1fc5f3c0fcf09d8dee90 Mon Sep 17 00:00:00 2001
From: Heesun Lee <heesun.task@gmail.com>
Date: Fri, 6 Mar 2026 21:18:12 -0800
Subject: [PATCH 1/3] contains duplicate solution

---
 contains-duplicate/heesun-task.js | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 contains-duplicate/heesun-task.js

diff --git a/contains-duplicate/heesun-task.js b/contains-duplicate/heesun-task.js
new file mode 100644
index 000000000..9dbce67dd
--- /dev/null
+++ b/contains-duplicate/heesun-task.js
@@ -0,0 +1,26 @@
+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+ /*
+    Goal: return true if duplicated #, false if no duplicated number
+
+    Plan:
+    - create a Set
+    - loop num in nums
+        - num exists in the Set -> return true
+        - not exsits ->  add the num in the Set, continue to the next loop
+    - return false 
+
+    space complexity: O(n)
+    time complexity: O(n)
+  */
+var containsDuplicate = function(nums) {
+    const seen = new Set();
+
+    for(const num of nums) {
+        if (seen.has(num)) return true;
+        seen.add(num);
+    }
+    return false; 
+};
\ No newline at end of file

From 1e540cd3e27b4b0525ac280aff915cb554a152e6 Mon Sep 17 00:00:00 2001
From: Heesun Lee <heesun.task@gmail.com>
Date: Fri, 6 Mar 2026 21:20:32 -0800
Subject: [PATCH 2/3] Add trailing newline at end of file

---
 contains-duplicate/heesun-task.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contains-duplicate/heesun-task.js b/contains-duplicate/heesun-task.js
index 9dbce67dd..ac5eb4b39 100644
--- a/contains-duplicate/heesun-task.js
+++ b/contains-duplicate/heesun-task.js
@@ -23,4 +23,4 @@ var containsDuplicate = function(nums) {
         seen.add(num);
     }
     return false; 
-};
\ No newline at end of file
+};

From 44a3f84d349eb2a51c5a3e042e9117b41e261c71 Mon Sep 17 00:00:00 2001
From: Heesun Lee <heesun.task@gmail.com>
Date: Fri, 6 Mar 2026 21:25:42 -0800
Subject: [PATCH 3/3] #1 two sum solution

---
 two-sum/heesun-task.js | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 two-sum/heesun-task.js

diff --git a/two-sum/heesun-task.js b/two-sum/heesun-task.js
new file mode 100644
index 000000000..40a36cca1
--- /dev/null
+++ b/two-sum/heesun-task.js
@@ -0,0 +1,33 @@
+/*
+    Goal: return indices of the two numbers such that they add up to target
+
+    Plan:
+    - create a hash map (dict) to store number -> index
+    - loop through nums with index i
+        - get currentNum = nums[i]
+        - compute pairNum = target - currentNum
+        - if pairNum exists in dict
+            -> return [dict[pairNum], i]
+        - otherwise store currentNum in dict with its index
+    - if no pair is found, return [-1, -1]
+
+    space complexity: O(n)
+    time complexity: O(n)
+*/
+
+var twoSum = function(nums, target) {
+    const dict = {};
+
+    for (let i = 0; i < nums.length; i++) {
+        const currentNum = nums[i];
+        const pairNum = target - currentNum;
+
+        if (typeof dict[pairNum] === 'number') {
+            return [dict[pairNum], i];
+        } else {
+            dict[currentNum] = i;
+        }
+    }
+
+    return [-1, -1];
+};