feat: solve two-sum

Author: sujeong-dev

two-sum/sujeong-dev.js

@@ -0,0 +1,32 @@
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+
+// 2중 for문: O(n^2)
+var twoSum = function (nums, target) {
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = 0; j < nums.length; j++) {
+      if (i === j) continue;
+      if (nums[i] + nums[j] === target) return [i, j];
+    }
+  }
+};
+
+// for loof: O(n)
+var twoSum = function (nums, target) {
+  let result = {};
+
+  nums.forEach((num, index) => {
+    result[num] = index;
+  });
+
+  for (let i = 0; i < nums.length; i++) {
+    const findNum = target - nums[i];
+
+    if (findNum in result && result[findNum] !== i) {
+      return [i, result[findNum]];
+    }
+  }
+};