two sum solution(py, js)

Author: hi-rachel

two-sum/hi-rachel.py

@@ -0,0 +1,50 @@
+"""
+처음 풀이
+O(N^2) time, O(N) space
+"""
+
+# class Solution:
+#     def twoSum(self, nums: List[int], target: int) -> List[int]:
+#         result = []
+#         for i in range(len(nums)):
+#             rest = target - nums[i]
+#             rest_nums = nums[i+1:]
+#             if rest in rest_nums:
+#                 result.extend([i, rest_nums.index(rest)+i+1])
+#                 break
+#         return result
+    
+
+"""
+개선 코드
+O(N) time, O(N) space
+"""
+
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        indices = {}
+        
+        for i, v in enumerate(nums):
+            diff = target - v
+            if diff in indices:
+                j = indices[diff]
+                return [i, j]
+            indices[v] = i
+
+# JS 풀이
+# /**
+#  * @param {number[]} nums
+#  * @param {number} target
+#  * @return {number[]}
+#  */
+# var twoSum = function(nums, target) {
+#     let indices = new Map();
+
+#     for (let i = 0; i < nums.length; i++) {
+#         diff = target - nums[i];
+#         if (indices.has(diff)) {
+#             return [i, indices.get(diff)];
+#         }
+#         indices.set(nums[i], i);
+#     }
+# };