feat(go/backtracking): add go code (#488)

* feat(go/backtracking): add go code

* feat(backtracking): add n_queens in go

* feat(backtracking): add /preorder_traversal_i_compact in go

* feat(backtracking): add /preorder_traversal_ii_compact in go

* feat(backtracking): add /preorder_traversal_ii_template in go

* feat(backtracking): add preorder_traversal_iii_compact in go

* feat(backtracking): add preorder_traversal_test in go

* feat(backtracking): add permutations_i in go

* feat(backtracking): add permutations_ii in go

* feat(backtracking): add permutation_test in go

* feat(backtracking): fix bug in go

* Update permutations_i.go

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/go/chapter_backtracking/n_queens_test.go

@@ -0,0 +1,24 @@
+// File: n_queens_test.go
+// Created Time: 2023-05-14
+// Author: Reanon (793584285@qq.com)
+
+package chapter_backtracking
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestNQueens(t *testing.T) {
+	n := 4
+	res := nQueens(n)
+
+	fmt.Println("输入棋盘长宽为 ", n)
+	fmt.Println("皇后放置方案共有 ", len(res), " 种")
+	for _, state := range res {
+		fmt.Println("--------------------")
+		for _, row := range state {
+			fmt.Println(row)
+		}
+	}
+}