feat: solve 3sum

Author: sujeong-dev

3sum/sujeong-dev.js

@@ -0,0 +1,24 @@
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ * 
+ * 시간복잡도: 이중 for문으로 O(n^2)이긴한데 너무 오래걸림
+ * 해설 확인해보기
+ */
+var threeSum = function (nums) {
+  if (nums.every((num) => num === 0)) return [nums.slice(0, 3)];
+
+  const threeSet = new Set();
+  for (let i = 0; i < nums.length - 2; i++) {
+    const twoSet = new Set();
+    for (let j = i + 1; j < nums.length; j++) {
+      const findNum = -(nums[i] + nums[j]);
+      if (twoSet.has(findNum)) {
+        const triplet = [nums[i], nums[j], findNum].sort((a, b) => a - b);
+        threeSet.add(triplet.join(','));
+      }
+      twoSet.add(nums[j]);
+    }
+  }
+  return Array.from(threeSet, (k) => k.split(',').map(Number));
+};