feat(soobing): two-sum

Author: soobing

two-sum/soobing.ts

@@ -0,0 +1,27 @@
+// 1. Brute force
+function twoSum(nums: number[], target: number): number[] {
+  for (let i = 0; i < nums.length - 1; i++) {
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[i] + nums[j] === target) {
+        return [i, j];
+      }
+    }
+  }
+  return [];
+}
+
+// 2. Hashmap
+function twoSum(nums: number[], target: number): number[] {
+  const map = new Map();
+  for (let i = 0; i < nums.length; i++) {
+    map.set(nums[i], i);
+  }
+
+  for (let i = 0; i < nums.length; i++) {
+    const targetIndex = map.get(target - nums[i]);
+    if (targetIndex && targetIndex !== i) {
+      return [i, targetIndex];
+    }
+  }
+  return [];
+}