feat: two-sum

Author: choidabom

two-sum/choidabom.ts

@@ -0,0 +1,36 @@
+// https://leetcode.com/problems/two-sum/
+
+// TC: O(n^2)
+// SC: O(1)
+
+function twoSum(nums: number[], target: number): number[] {
+    for (let i = 0; i < nums.length; i++) {
+      for (let j = i + 1; j < nums.length; j++){
+        if (nums[i] + nums[j] === target){
+          return [i, j]
+        }
+      }
+    }
+    return []
+};
+
+// TC: O(n)
+// SC: O(n)
+
+function twoSum(nums: number[], target: number): number[] {
+    const map = new Map()
+
+    for (let i = 0; i < nums.length; i++) {
+        const num = nums[i]
+        const diff = target - num
+
+        if (map.has(diff)) {
+            return [i, map.get(diff)]
+        } else {
+            map.set(num, i)
+        }
+    }
+    return []
+};
+
+console.log(twoSum([2,7,11,15], 9))