Refactor the articles related to searching algorithm. Add the chapter of binary search. Add the section of searching algorithm revisited. (#464)

codes/go/chapter_searching/leetcode_two_sum.go

@@ -0,0 +1,33 @@
+// File: leetcode_two_sum.go
+// Created Time: 2022-11-25
+// Author: reanon (793584285@qq.com)
+
+package chapter_searching
+
+/* 方法一：暴力枚举 */
+func twoSumBruteForce(nums []int, target int) []int {
+	size := len(nums)
+	// 两层循环，时间复杂度 O(n^2)
+	for i := 0; i < size-1; i++ {
+		for j := i + 1; i < size; j++ {
+			if nums[i]+nums[j] == target {
+				return []int{i, j}
+			}
+		}
+	}
+	return nil
+}
+
+/* 方法二：辅助哈希表 */
+func twoSumHashTable(nums []int, target int) []int {
+	// 辅助哈希表，空间复杂度 O(n)
+	hashTable := map[int]int{}
+	// 单层循环，时间复杂度 O(n)
+	for idx, val := range nums {
+		if preIdx, ok := hashTable[target-val]; ok {
+			return []int{preIdx, idx}
+		}
+		hashTable[val] = idx
+	}
+	return nil
+}