Add JS for chapter of computational complexity

codes/javascript/chapter_computational_complexity/leetcode_two_sum.js

@@ -0,0 +1,36 @@
+/*
+ * @Author: gyt95 (gytkwan@gmail.com)
+ * @Date: 2022-12-15 10:51:54 
+ * @Last Modified by: gyt95 (gytkwan@gmail.com)
+ * @Last Modified time: 2022-12-15 10:56:26
+ */
+
+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+function twoSumBruteForce(nums, target) {
+  let n = nums.length;
+  // 两层循环，时间复杂度 O(n^2)
+  for (let i = 0; i < n; i++) {
+    for (let j = i + 1; j < n; j++) {
+      if (nums[i] + nums[j] === target) {
+        return [i, j]
+      }
+    }
+  }
+}
+
+function twoSumHashTable(nums, target) {
+  // 辅助哈希表，空间复杂度 O(n)
+  let m = {}
+  // 单层循环，时间复杂度 O(n)
+  for (let i = 0; i < nums.length; i++) {
+    if (m[nums[i]] !== undefined) {
+      return [m[nums[i]], i]
+    } else {
+      m[target - nums[i]] = i;
+    }
+  }
+}

docs/chapter_computational_complexity/space_time_tradeoff.md

@@ -90,7 +90,17 @@ comments: true
 === "JavaScript"
 
     ```js title="leetcode_two_sum.js"
-
+    function twoSumBruteForce(nums, target) {
+      let n = nums.length;
+      // 两层循环，时间复杂度 O(n^2)
+      for (let i = 0; i < n; i++) {
+        for (let j = i + 1; j < n; j++) {
+          if (nums[i] + nums[j] === target) {
+            return [i, j]
+          }
+        }
+      }
+    }
     ```
 
 === "TypeScript"
@@ -193,7 +203,18 @@ comments: true
 === "JavaScript"
 
     ```js title="leetcode_two_sum.js"
-
+    function twoSumHashTable(nums, target) {
+      // 辅助哈希表，空间复杂度 O(n)
+      let m = {}
+      // 单层循环，时间复杂度 O(n)
+      for (let i = 0; i < nums.length; i++) {
+        if (m[nums[i]] !== undefined) {
+          return [m[nums[i]], i]
+        } else {
+          m[target - nums[i]] = i;
+        }
+      }
+    }
     ```
 
 === "TypeScript"