From 09d89dc9ad0645e35c320f7fcf7aa58c79fd44ab Mon Sep 17 00:00:00 2001
From: reanon <793584285@qq.com>
Date: Thu, 24 Nov 2022 22:54:10 +0800
Subject: [PATCH] feat(chapter1): add go code to chapter1 1.add go code to
 chapter_computational_complexity 2.add go code to space_time_tradeoff.md 3.
 Indentation of Go code is tab in *.go , 4 spaces in *.md

---
 .gitignore                                    |  1 +
 .../leetcode_two_sum.go                       | 30 +++++++++++++++
 .../leetcode_two_sum_test.go                  | 24 ++++++++++++
 codes/go/go.mod                               |  3 ++
 .../space_time_tradeoff.md                    | 37 ++++++++++++++++++-
 5 files changed, 93 insertions(+), 2 deletions(-)
 create mode 100644 codes/go/chapter_computational_complexity/leetcode_two_sum.go
 create mode 100644 codes/go/chapter_computational_complexity/leetcode_two_sum_test.go
 create mode 100644 codes/go/go.mod

diff --git a/.gitignore b/.gitignore
index e07ebeabb..8e6eb4d93 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 
 # Editor
 .vscode/
+.idea/
 
 # mkdocs files
 site/
diff --git a/codes/go/chapter_computational_complexity/leetcode_two_sum.go b/codes/go/chapter_computational_complexity/leetcode_two_sum.go
new file mode 100644
index 000000000..c3c34f99f
--- /dev/null
+++ b/codes/go/chapter_computational_complexity/leetcode_two_sum.go
@@ -0,0 +1,30 @@
+// File: leetcode_two_sum.go
+// Created Time: 2022-11-25
+// Author: reanon (793584285@qq.com)
+
+package chapter_computational_complexity
+
+// twoSumBruteForce
+func twoSumBruteForce(nums []int, target int) []int {
+	size := len(nums)
+	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
+}
+
+// twoSumHashTable
+func twoSumHashTable(nums []int, target int) []int {
+	hashTable := map[int]int{}
+	for idx, val := range nums {
+		if preIdx, ok := hashTable[target-val]; ok {
+			return []int{preIdx, idx}
+		}
+		hashTable[val] = idx
+	}
+	return nil
+}
diff --git a/codes/go/chapter_computational_complexity/leetcode_two_sum_test.go b/codes/go/chapter_computational_complexity/leetcode_two_sum_test.go
new file mode 100644
index 000000000..9ddf9ea38
--- /dev/null
+++ b/codes/go/chapter_computational_complexity/leetcode_two_sum_test.go
@@ -0,0 +1,24 @@
+// File: leetcode_two_sum.go
+// Created Time: 2022-11-25
+// Author: reanon (793584285@qq.com)
+
+package chapter_computational_complexity
+
+import (
+	"testing"
+)
+
+func TestTwoSum(t *testing.T) {
+	// ======= Test Case =======
+	nums := []int{2, 7, 11, 15}
+	target := 9
+
+	// ====== Driver Code ======
+	// 方法一：暴力解法
+	res := twoSumBruteForce(nums, target)
+	t.Log("brute force:", res)
+
+	// 方法二：哈希表
+	res = twoSumHashTable(nums, target)
+	t.Log("hash table:", res)
+}
diff --git a/codes/go/go.mod b/codes/go/go.mod
new file mode 100644
index 000000000..34f5dac20
--- /dev/null
+++ b/codes/go/go.mod
@@ -0,0 +1,3 @@
+module github.com/krahets/hello-algo
+
+go 1.19
diff --git a/docs/chapter_computational_complexity/space_time_tradeoff.md b/docs/chapter_computational_complexity/space_time_tradeoff.md
index 3753f050c..0f82f6c43 100644
--- a/docs/chapter_computational_complexity/space_time_tradeoff.md
+++ b/docs/chapter_computational_complexity/space_time_tradeoff.md
@@ -33,7 +33,7 @@
 === "C++"
 
     ```cpp title="leetcode_two_sum.cpp"
-
+    
     ```
 
 === "Python"
@@ -42,6 +42,24 @@
     
     ```
 
+=== "Go"
+
+    ```go title="leetcode_two_sum.go"
+    func twoSum(nums []int, target int) []int {
+        size := len(nums)
+        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
 
 时间复杂度 $O(N)$ ，空间复杂度 $O(N)$ ，属于「空间换时间」。
@@ -69,7 +87,7 @@
 === "C++"
 
     ```cpp title="leetcode_two_sum.cpp"
-
+    
     ```
 
 === "Python"
@@ -77,3 +95,18 @@
     ```python title="leetcode_two_sum.py"
     
     ```
+
+=== "Go"
+
+    ```go title="leetcode_two_sum.go"
+    func twoSumHashTable(nums []int, target int) []int {
+        hashTable := map[int]int{}
+        for idx, val := range nums {
+            if preIdx, ok := hashTable[target-val]; ok {
+                return []int{preIdx, idx}
+            }
+            hashTable[val] = idx
+        }
+        return nil
+    }
+    ```