Translate all code to English (#1836)

* Review the EN heading format. * Fix pythontutor headings. * Fix pythontutor headings. * bug fixes * Fix headings in **/summary.md * Revisit the CN-to-EN translation for Python code using Claude-4.5 * Revisit the CN-to-EN translation for Java code using Claude-4.5 * Revisit the CN-to-EN translation for Cpp code using Claude-4.5. * Fix the dictionary. * Fix cpp code translation for the multipart strings. * Translate Go code to English. * Update workflows to test EN code. * Add EN translation for C. * Add EN translation for CSharp. * Add EN translation for Swift. * Trigger the CI check. * Revert. * Update en/hash_map.md * Add the EN version of Dart code. * Add the EN version of Kotlin code. * Add missing code files. * Add the EN version of JavaScript code. * Add the EN version of TypeScript code. * Fix the workflows. * Add the EN version of Ruby code. * Add the EN version of Rust code. * Update the CI check for the English version code. * Update Python CI check. * Fix cmakelists for en/C code. * Fix Ruby comments
2026-08-13 12:20:57 +00:00 · 2025-12-31 07:44:52 +08:00
parent 45e1295241
commit 2778a6f9c7
1284 changed files with 71557 additions and 3275 deletions
@@ -0,0 +1,78 @@
+/**
+ * File: recursion.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_computational_complexity.recursion
+
+import java.util.*
+
+/* Recursion */
+fun recur(n: Int): Int {
+    // Termination condition
+    if (n == 1)
+        return 1
+    // Descend: recursive call
+    val res = recur(n - 1)
+    // Return: return result
+    return n + res
+}
+
+/* Simulate recursion using iteration */
+fun forLoopRecur(n: Int): Int {
+    // Use an explicit stack to simulate the system call stack
+    val stack = Stack<Int>()
+    var res = 0
+    // Descend: recursive call
+    for (i in n downTo 0) {
+        // Simulate "recurse" with "push"
+        stack.push(i)
+    }
+    // Return: return result
+    while (stack.isNotEmpty()) {
+        // Simulate "return" with "pop"
+        res += stack.pop()
+    }
+    // res = 1+2+3+...+n
+    return res
+}
+
+/* Tail recursion */
+tailrec fun tailRecur(n: Int, res: Int): Int {
+    // Add tailrec keyword to enable tail recursion optimization
+    // Termination condition
+    if (n == 0)
+        return res
+    // Tail recursive call
+    return tailRecur(n - 1, res + n)
+}
+
+/* Fibonacci sequence: recursion */
+fun fib(n: Int): Int {
+    // Termination condition f(1) = 0, f(2) = 1
+    if (n == 1 || n == 2)
+        return n - 1
+    // Recursive call f(n) = f(n-1) + f(n-2)
+    val res = fib(n - 1) + fib(n - 2)
+    // Return result f(n)
+    return res
+}
+
+/* Driver Code */
+fun main() {
+    val n = 5
+    var res: Int
+
+    res = recur(n)
+    println("\nRecursion sum result res = $res")
+
+    res = forLoopRecur(n)
+    println("\nUsing iteration to simulate recursion sum result res = $res")
+
+    res = tailRecur(n, 0)
+    println("\nTail recursion sum result res = $res")
+
+    res = fib(n)
+    println("\nThe ${n}th Fibonacci number is $res")
+}