풀이1: 3Sum #241

Author: seungseung88

3sum/seungseung88.js

@@ -0,0 +1,35 @@
+/**
+ *
+ * 시간 복잡도: O(n log n) + O(n^2) => O(n^2)
+ * 공간 복잡도: O(1)
+ * - 자바스크립트 배열은 원래의 배열 자체를 바꿈
+ */
+const threeSum = (numbers) => {
+  let result = [];
+  numbers.sort((a, b) => a - b);
+
+  for (let i = 0; i < numbers.length; i += 1) {
+    if (i > 0 && numbers[i] === numbers[i - 1]) continue;
+
+    let l = i + 1;
+    let r = numbers.length - 1;
+
+    while (l < r) {
+      const threeSum = numbers[i] + numbers[l] + numbers[r];
+
+      if (threeSum > 0) {
+        r -= 1;
+      } else if (threeSum < 0) {
+        l += 1;
+      } else {
+        result.push([numbers[i], numbers[l], numbers[r]]);
+        while (l < r && numbers[l] === numbers[l + 1]) l += 1;
+        while (l < r && numbers[r] === numbers[r - 1]) r -= 1;
+        l += 1;
+        r -= 1;
+      }
+    }
+  }
+
+  return result;
+};