feat(go): add iterration/recursion & fix bugs (#698)

codes/c/chapter_heap/my_heap.c

@@ -28,7 +28,7 @@ maxHeap *newMaxHeap(int nums[], int size) {
     maxHeap *h = (maxHeap *)malloc(sizeof(maxHeap));
     h->size = size;
     memcpy(h->data, nums, size * sizeof(int));
-    for (int i = size - 1; i >= 0; i--) {
+    for (int i = parent(size - 1); i >= 0; i--) {
         // 堆化除叶节点以外的其他所有节点
         siftDown(h, i);
     }

codes/go/chapter_computational_complexity/iteration.go

@@ -0,0 +1,59 @@
+// File: iteration.go
+// Created Time: 2023-08-28
+// Author: Reanon (793584285@qq.com)
+
+package chapter_computational_complexity
+
+import "fmt"
+
+/* for 循环 */
+func forLoop(n int) int {
+	res := 0
+	// 循环求和 1, 2, ..., n-1, n
+	for i := 1; i <= n; i++ {
+		res += i
+	}
+	return res
+}
+
+/* while 循环 */
+func whileLoop(n int) int {
+	res := 0
+	// 初始化条件变量
+	i := 1
+	// 循环求和 1, 2, ..., n-1, n
+	for i <= n {
+		res += i
+		// 更新条件变量
+		i++
+	}
+	return res
+}
+
+/* while 循环（两次更新） */
+func whileLoopII(n int) int {
+	res := 0
+	// 初始化条件变量
+	i := 1
+	// 循环求和 1, 4, ...
+	for i <= n {
+		res += i
+		// 更新条件变量
+		i++
+		i *= 2
+	}
+	return res
+}
+
+/* 双层 for 循环 */
+func nestedForLoop(n int) string {
+	res := ""
+	// 循环 i = 1, 2, ..., n-1, n
+	for i := 1; i <= n; i++ {
+		for j := 1; j <= n; j++ {
+			// 循环 j = 1, 2, ..., n-1, n
+			res += fmt.Sprintf("(%d, %d), ", i, j)
+		}
+	}
+	return res
+}

codes/go/chapter_computational_complexity/iteration_test.go

@@ -0,0 +1,26 @@
+// File: iteration_test.go
+// Created Time: 2023-08-28
+// Author: Reanon (793584285@qq.com)
+
+package chapter_computational_complexity
+
+import (
+	"fmt"
+	"testing"
+)
+
+/* Driver Code */
+func TestIteration(t *testing.T) {
+	n := 5
+	res := forLoop(n)
+	fmt.Println("\nfor 循环的求和结果 res = ", res)
+
+	res = whileLoop(n)
+	fmt.Println("\nwhile 循环的求和结果 res = ", res)
+
+	res = whileLoopII(n)
+	fmt.Println("\nwhile 循环（两次更新）求和结果 res = ", res)
+
+	resStr := nestedForLoop(n)
+	fmt.Println("\n双层 for 循环的遍历结果 ", resStr)
+}

codes/go/chapter_computational_complexity/recursion.go

@@ -0,0 +1,39 @@
+// File: recursion.go
+// Created Time: 2023-08-28
+// Author: Reanon (793584285@qq.com)
+
+package chapter_computational_complexity
+
+/* 递归 */
+func recur(n int) int {
+	// 终止条件
+	if n == 1 {
+		return 1
+	}
+	// 递：递归调用
+	res := recur(n - 1)
+	// 归：返回结果
+	return n + res
+}
+
+/* 尾递归 */
+func tailRecur(n int, res int) int {
+	// 终止条件
+	if n == 0 {
+		return res
+	}
+	// 尾递归调用
+	return tailRecur(n-1, res+n)
+}
+
+/* 斐波那契数列：递归 */
+func fib(n int) int {
+	// 终止条件 f(1) = 0, f(2) = 1
+	if n == 1 || n == 2 {
+		return n - 1
+	}
+	// 递归调用 f(n) = f(n-1) + f(n-2)
+	res := fib(n-1) + fib(n-2)
+	// 返回结果 f(n)
+	return res
+}

codes/go/chapter_computational_complexity/recursion_test.go

@@ -0,0 +1,23 @@
+// File: recursion_test.go
+// Created Time: 2023-08-28
+// Author: Reanon (793584285@qq.com)
+
+package chapter_computational_complexity
+
+import (
+	"fmt"
+	"testing"
+)
+
+/* Driver Code */
+func TestRecursion(t *testing.T) {
+	n := 5
+	res := recur(n)
+	fmt.Println("\n递归函数的求和结果 res = ", res)
+
+	res = tailRecur(n, 0)
+	fmt.Println("\n尾递归函数的求和结果 res = ", res)
+
+	res = fib(n)
+	fmt.Println("\n斐波那契数列的第", n, "项为", res)
+}

codes/go/chapter_heap/my_heap.go

@@ -26,7 +26,7 @@ func newHeap() *maxHeap {
 func newMaxHeap(nums []any) *maxHeap {
 	// 将列表元素原封不动添加进堆
 	h := &maxHeap{data: nums}
-	for i := len(h.data) - 1; i >= 0; i-- {
+	for i := h.parent(len(h.data) - 1); i >= 0; i-- {
 		// 堆化除叶节点以外的其他所有节点
 		h.siftDown(i)
 	}