From 620bfb1f1d566f770cf7e4e2520e2779519e17b5 Mon Sep 17 00:00:00 2001
From: gaofer <35647389+gaofer@users.noreply.github.com>
Date: Sat, 2 Sep 2023 16:09:13 +0800
Subject: [PATCH] Iteration and recursion code in js/ts (#703)

* feat(JS and TS):add the section of iteration and recursion

* feat(JS and TS):add the section of iteration and recursion

* feat(JS and TS):add the section of iteration and recursion
---
 .../iteration.js                              | 70 ++++++++++++++++++
 .../recursion.js                              | 46 ++++++++++++
 .../iteration.ts                              | 72 +++++++++++++++++++
 .../recursion.ts                              | 48 +++++++++++++
 4 files changed, 236 insertions(+)
 create mode 100644 codes/javascript/chapter_computational_complexity/iteration.js
 create mode 100644 codes/javascript/chapter_computational_complexity/recursion.js
 create mode 100644 codes/typescript/chapter_computational_complexity/iteration.ts
 create mode 100644 codes/typescript/chapter_computational_complexity/recursion.ts

diff --git a/codes/javascript/chapter_computational_complexity/iteration.js b/codes/javascript/chapter_computational_complexity/iteration.js
new file mode 100644
index 000000000..abf8ae70d
--- /dev/null
+++ b/codes/javascript/chapter_computational_complexity/iteration.js
@@ -0,0 +1,70 @@
+/**
+ * File: iteration.js
+ * Created Time: 2023-08-28
+ * Author: Gaofer Chou (gaofer-chou@qq.com)
+ */
+
+/* for 循环 */
+function forLoop(n) {
+    let res = 0;
+    // 循环求和 1, 2, ..., n-1, n
+    for (let i = 1; i <= n; i++) {
+        res += i;
+    }
+    return res;
+}
+
+/* while 循环 */
+function whileLoop(n) {
+    let res = 0;
+    let i = 1; // 初始化条件变量
+    // 循环求和 1, 2, ..., n-1, n
+    while (i <= n) {
+        res += i;
+        i++; // 更新条件变量
+    }
+    return res;
+}
+
+/* while 循环（两次更新） */
+function whileLoopII(n) {
+    let res = 0;
+    let i = 1; // 初始化条件变量
+    // 循环求和 1, 4, ...
+    while (i <= n) {
+        res += i;
+        // 更新条件变量
+        i++;
+        i *= 2;
+    }
+    return res;
+}
+
+/* 双层 for 循环 */
+function nestedForLoop(n) {
+    let res = '';
+    // 循环 i = 1, 2, ..., n-1, n
+    for (let i = 1; i <= n; i++) {
+        // 循环 j = 1, 2, ..., n-1, n
+        for (let j = 1; j <= n; j++) {
+            res += `(${i}, ${j}), `;
+        }
+    }
+    return res;
+}
+
+/* Driver Code */
+const n = 5;
+let res;
+
+res = forLoop(n);
+console.log(`for 循环的求和结果 res = ${res}`);
+
+res = whileLoop(n);
+console.log(`while 循环的求和结果 res = ${res}`);
+
+res = whileLoopII(n);
+console.log(`while 循环（两次更新）求和结果 res = ${res}`);
+
+const resStr = nestedForLoop(n);
+console.log(`双层 for 循环的遍历结果 ${resStr}`);
diff --git a/codes/javascript/chapter_computational_complexity/recursion.js b/codes/javascript/chapter_computational_complexity/recursion.js
new file mode 100644
index 000000000..48538ac79
--- /dev/null
+++ b/codes/javascript/chapter_computational_complexity/recursion.js
@@ -0,0 +1,46 @@
+/**
+ * File: recursion.js
+ * Created Time: 2023-08-28
+ * Author: Gaofer Chou (gaofer-chou@qq.com)
+ */
+
+/* 递归 */
+function recur(n) {
+    // 终止条件
+    if (n === 1) return 1;
+    // 递：递归调用
+    const res = recur(n - 1);
+    // 归：返回结果
+    return n + res;
+}
+
+/* 尾递归 */
+function tailRecur(n, res) {
+    // 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 */
+function fib(n) {
+    // 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)
+    const res = fib(n - 1) + fib(n - 2);
+    // 返回结果 f(n)
+    return res;
+}
+
+/* Driver Code */
+const n = 5;
+let res;
+
+res = recur(n);
+console.log(`递归函数的求和结果 res = ${res}`);
+
+res = tailRecur(n, 0);
+console.log(`尾递归函数的求和结果 res = ${res}`);
+
+res = fib(n);
+console.log(`斐波那契数列的第 ${n} 项为 ${res}`);
diff --git a/codes/typescript/chapter_computational_complexity/iteration.ts b/codes/typescript/chapter_computational_complexity/iteration.ts
new file mode 100644
index 000000000..8ecd6d8a7
--- /dev/null
+++ b/codes/typescript/chapter_computational_complexity/iteration.ts
@@ -0,0 +1,72 @@
+/**
+ * File: iteration.ts
+ * Created Time: 2023-08-28
+ * Author: Gaofer Chou (gaofer-chou@qq.com)
+ */
+
+/* for 循环 */
+function forLoop(n: number): number {
+    let res = 0;
+    // 循环求和 1, 2, ..., n-1, n
+    for (let i = 1; i <= n; i++) {
+        res += i;
+    }
+    return res;
+}
+
+/* while 循环 */
+function whileLoop(n: number): number {
+    let res = 0;
+    let i = 1; // 初始化条件变量
+    // 循环求和 1, 2, ..., n-1, n
+    while (i <= n) {
+        res += i;
+        i++; // 更新条件变量
+    }
+    return res;
+}
+
+/* while 循环（两次更新） */
+function whileLoopII(n: number): number {
+    let res = 0;
+    let i = 1; // 初始化条件变量
+    // 循环求和 1, 4, ...
+    while (i <= n) {
+        res += i;
+        // 更新条件变量
+        i++;
+        i *= 2;
+    }
+    return res;
+}
+
+/* 双层 for 循环 */
+function nestedForLoop(n: number): string {
+    let res = '';
+    // 循环 i = 1, 2, ..., n-1, n
+    for (let i = 1; i <= n; i++) {
+        // 循环 j = 1, 2, ..., n-1, n
+        for (let j = 1; j <= n; j++) {
+            res += `(${i}, ${j}), `;
+        }
+    }
+    return res;
+}
+
+/* Driver Code */
+const n = 5;
+let res: number;
+
+res = forLoop(n);
+console.log(`for 循环的求和结果 res = ${res}`);
+
+res = whileLoop(n);
+console.log(`while 循环的求和结果 res = ${res}`);
+
+res = whileLoopII(n);
+console.log(`while 循环（两次更新）求和结果 res = ${res}`);
+
+const resStr = nestedForLoop(n);
+console.log(`双层 for 循环的遍历结果 ${resStr}`);
+
+export {};
\ No newline at end of file
diff --git a/codes/typescript/chapter_computational_complexity/recursion.ts b/codes/typescript/chapter_computational_complexity/recursion.ts
new file mode 100644
index 000000000..eb0246eb0
--- /dev/null
+++ b/codes/typescript/chapter_computational_complexity/recursion.ts
@@ -0,0 +1,48 @@
+/**
+ * File: recursion.ts
+ * Created Time: 2023-08-28
+ * Author: Gaofer Chou (gaofer-chou@qq.com)
+ */
+
+/* 递归 */
+function recur(n: number): number {
+    // 终止条件
+    if (n === 1) return 1;
+    // 递：递归调用
+    const res = recur(n - 1);
+    // 归：返回结果
+    return n + res;
+}
+
+/* 尾递归 */
+function tailRecur(n: number, res: number): number {
+    // 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 */
+function fib(n: number): number {
+    // 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)
+    const res = fib(n - 1) + fib(n - 2);
+    // 返回结果 f(n)
+    return res;
+}
+
+/* Driver Code */
+const n = 5;
+let res: number;
+
+res = recur(n);
+console.log(`递归函数的求和结果 res = ${res}`);
+
+res = tailRecur(n, 0);
+console.log(`尾递归函数的求和结果 res = ${res}`);
+
+res = fib(n);
+console.log(`斐波那契数列的第 ${n} 项为 ${res}`);
+
+export {};
\ No newline at end of file