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add php code #1826

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0ed4b5d
第二章 复杂度分析 增加PHP 代码示例
piaohan Nov 7, 2025
04d086a
第二章 自检
piaohan Nov 7, 2025
b4471ed
第二章 规范化
piaohan Nov 19, 2025
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11 changes: 6 additions & 5 deletions codes/php/chapter_computational_complexity/iteration.php
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Original file line number Diff line number Diff line change
Expand Up @@ -7,10 +7,10 @@

namespace chapter_computational_complexity;

class Iteration
class iteration
{
/* for 循环 */
public static function forLoop($n)
public static function forLoop($n): int
{
$res = 0;
// 循环求和 1, 2, ..., n-1, n
Expand All @@ -21,7 +21,7 @@ public static function forLoop($n)
}

/* while 循环 */
public static function whileLoop($n)
public static function whileLoop($n): int
{
$res = 0;
$i = 1; // 初始化条件变量
Expand All @@ -34,7 +34,7 @@ public static function whileLoop($n)
}

/* while 循环（两次更新） */
public static function whileLoopII($n)
public static function whileLoopII($n): int
{
$res = 0;
$i = 1; // 初始化条件变量
Expand All @@ -49,7 +49,7 @@ public static function whileLoopII($n)
}

/* 双层 for 循环 */
public static function nestedForLoop($n)
public static function nestedForLoop($n): string
{
$res = '';
// 循环 i = 1, 2, ..., n-1, n
Expand All @@ -62,6 +62,7 @@ public static function nestedForLoop($n)
return $res;
}
}

/* Driver Code */
$n = 5;

Expand Down
12 changes: 6 additions & 6 deletions codes/php/chapter_computational_complexity/recursion.php
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Expand Up @@ -7,9 +7,9 @@

namespace chapter_computational_complexity;

class Recursion
class recursion
{
// 递归
/* 递归 */
public static function recur(int $n): int
{
// 终止条件
Expand All @@ -22,7 +22,7 @@ public static function recur(int $n): int
return $n + $res;
}

// 使用迭代模拟递归
/* 使用迭代模拟递归 */
public static function forLoopRecur(int $n): int
{
// 使用一个显式的数组来模拟系统调用栈
Expand All @@ -42,7 +42,7 @@ public static function forLoopRecur(int $n): int
return $res;
}

// 尾递归
/* 尾递归 */
public static function tailRecur(int $n, int $res): int
{
// 终止条件
Expand All @@ -53,7 +53,7 @@ public static function tailRecur(int $n, int $res): int
return self::tailRecur($n - 1, $res + $n);
}

// 斐波那契数列：递归
/* 斐波那契数列：递归 */
public static function fib(int $n): int
{
// 终止条件 f(1) = 0, f(2) = 1
Expand All @@ -69,7 +69,7 @@ public static function fib(int $n): int

}

// Driver Code
/* Driver Code */
$n = 5;
$res = 0;
Recursion::recur($n);
Expand Down
32 changes: 15 additions & 17 deletions codes/php/chapter_computational_complexity/space_complexity.php
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Expand Up @@ -6,16 +6,16 @@
*/

namespace chapter_computational_complexity;
class SpaceComplexity
class space_complexity

@krahets krahets Nov 19, 2025 •
edited
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We should use CamelCase for class names in PHP. Same as all other class names.

Please carefully check the code and ensure that the code follows the coding standard of PHP.

{
// 函数
/* 函数 */
public static function functionMethod(): int
{
// 执行某些操作
return 0;
}

// 常数阶
/* 常数阶 */
public static function constant(int $n): void
{
// 常量、变量、对象占用 O(1) 空间
Expand All @@ -32,7 +32,7 @@ public static function constant(int $n): void
}
}

// 线性阶
/* 线性阶 */
public static function linear(int $n): void
{
// 长度为 n 的数组占用 O(n) 空间
Expand All @@ -49,7 +49,7 @@ public static function linear(int $n): void
}
}

// 线性阶（递归实现）
/* 线性阶（递归实现）*/
public static function linearRecur(int $n): void
{
echo "递归 n = " . $n . "\n";
Expand All @@ -59,7 +59,7 @@ public static function linearRecur(int $n): void
self::linearRecur($n - 1);
}

// 平方阶
/* 平方阶 */
public static function quadratic(int $n): void
{
// 矩阵占用 O(n^2) 空间
Expand All @@ -78,7 +78,7 @@ public static function quadratic(int $n): void
}
}

// 平方阶（递归实现）
/* 平方阶（递归实现） */
public static function quadraticRecur(int $n): int
{
if ($n <= 0) {
Expand All @@ -90,7 +90,7 @@ public static function quadraticRecur(int $n): int
return self::quadraticRecur($n - 1);
}

// 指数阶（建立满二叉树）
/* 指数阶（建立满二叉树）*/
public static function buildTree(int $n)
{
if ($n == 0) {
Expand All @@ -101,20 +101,18 @@ public static function buildTree(int $n)
$root['right'] = self::buildTree($n - 1);
return $root;
}

// Driver Code
}

// Driver Code
/* Driver Code */
$n = 5;
// 常数阶
SpaceComplexity::constant($n);
space_complexity::constant($n);
// 线性阶
SpaceComplexity::linear($n);
SpaceComplexity::linearRecur($n);
space_complexity::linear($n);
space_complexity::linearRecur($n);
// 平方阶
SpaceComplexity::quadratic($n);
SpaceComplexity::quadraticRecur($n);
space_complexity::quadratic($n);
space_complexity::quadraticRecur($n);
// 指数阶
$root = SpaceComplexity::buildTree($n);
$root = space_complexity::buildTree($n);
echo "指数阶（建立满二叉树）完成\n";
79 changes: 39 additions & 40 deletions codes/php/chapter_computational_complexity/time_complexity.php
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,9 @@

namespace chapter_computational_complexity;

class TimeComplexity
class time_complexity
{
// 常数阶
/* 常数阶 */
public static function constant(int $n): int
{
$count = 0;
Expand All @@ -20,7 +20,7 @@ public static function constant(int $n): int
return $count;
}

// 线性阶
/* 线性阶 */
public static function linear(int $n): int
{
$count = 0;
Expand All @@ -30,7 +30,7 @@ public static function linear(int $n): int
return $count;
}

// 线性阶（遍历数组）
/* 线性阶（遍历数组）*/
public static function arrayTraversal(array $nums): int
{
$count = 0;
Expand All @@ -41,7 +41,7 @@ public static function arrayTraversal(array $nums): int
return $count;
}

// 平方阶
/* 平方阶 */
public static function quadratic(int $n): int
{
$count = 0;
Expand All @@ -54,7 +54,7 @@ public static function quadratic(int $n): int
return $count;
}

// 平方阶（冒泡排序）
/* 平方阶（冒泡排序）*/
public static function bubbleSort(array &$nums): int
{
$count = 0; // 计数器
Expand All @@ -74,7 +74,7 @@ public static function bubbleSort(array &$nums): int
return $count;
}

// 指数阶（循环实现）
/* 指数阶（循环实现）*/
public static function exponential(int $n): int
{
$count = 0;
Expand All @@ -90,7 +90,7 @@ public static function exponential(int $n): int
return $count;
}

// 指数阶（递归实现）
/* 指数阶（递归实现）*/
public static function expRecur(int $n): int
{
if ($n == 1) {
Expand All @@ -99,40 +99,40 @@ public static function expRecur(int $n): int
return self::expRecur($n - 1) + self::expRecur($n - 1) + 1;
}

// 对数阶（循环实现）
/* 对数阶（循环实现）*/
public static function logarithmic(int $n): int
{
$count = 0;
while ($n > 1) {
$n = (int)($n / 2);
$n = (int) ($n / 2);
$count++;
}
return $count;
}

// 对数阶（递归实现）
/* 对数阶（递归实现）*/
public static function logRecur(int $n): int
{
if ($n <= 1) {
return 0;
}
return self::logRecur((int)($n / 2)) + 1;
return self::logRecur((int) ($n / 2)) + 1;
}

// 线性对数阶
/* 线性对数阶 */
public static function linearLogRecur(int $n): int
{
if ($n <= 1) {
return 1;
}
$count = self::linearLogRecur((int)($n / 2)) + self::linearLogRecur((int)($n / 2));
$count = self::linearLogRecur((int) ($n / 2)) + self::linearLogRecur((int) ($n / 2));
for ($i = 0; $i < $n; $i++) {
$count++;
}
return $count;
}

// 阶乘阶（递归实现）
/* 阶乘阶（递归实现）*/
public static function factorialRecur(int $n): int
{
if ($n == 0) {
Expand All @@ -148,40 +148,39 @@ public static function factorialRecur(int $n): int

}

// Driver Code
// 可以修改 n 运行，体会一下各种复杂度的操作数量变化趋势
/* Driver Code */
$n = 8;
echo "输入数据大小 n = " . $n . "\n";
echo "输入数据大小 n = ".$n."\n";

$count = TimeComplexity::constant($n);
echo "常数阶的操作数量 = " . $count . "\n";
$count = time_complexity::constant($n);
echo "常数阶的操作数量 = ".$count."\n";

$count = TimeComplexity::linear($n);
echo "线性阶的操作数量 = " . $count . "\n";
$count = TimeComplexity::arrayTraversal(array_fill(0, $n, 0));
echo "线性阶（遍历数组）的操作数量 = " . $count . "\n";
$count = time_complexity::linear($n);
echo "线性阶的操作数量 = ".$count."\n";
$count = time_complexity::arrayTraversal(array_fill(0, $n, 0));
echo "线性阶（遍历数组）的操作数量 = ".$count."\n";

$count = TimeComplexity::quadratic($n);
echo "平方阶的操作数量 = " . $count . "\n";
$count = time_complexity::quadratic($n);
echo "平方阶的操作数量 = ".$count."\n";
$nums = array_fill(0, $n, 0);
for ($i = 0; $i < $n; $i++) {
$nums[$i] = $n - $i; // [n,n-1,...,2,1]
}
$count = TimeComplexity::bubbleSort($nums);
echo "平方阶（冒泡排序）的操作数量 = " . $count . "\n";
$count = time_complexity::bubbleSort($nums);
echo "平方阶（冒泡排序）的操作数量 = ".$count."\n";

$count = TimeComplexity::exponential($n);
echo "指数阶（循环实现）的操作数量 = " . $count . "\n";
$count = TimeComplexity::expRecur($n);
echo "指数阶（递归实现）的操作数量 = " . $count . "\n";
$count = time_complexity::exponential($n);
echo "指数阶（循环实现）的操作数量 = ".$count."\n";
$count = time_complexity::expRecur($n);
echo "指数阶（递归实现）的操作数量 = ".$count."\n";

$count = TimeComplexity::logarithmic($n);
echo "对数阶（循环实现）的操作数量 = " . $count . "\n";
$count = TimeComplexity::logRecur($n);
echo "对数阶（递归实现）的操作数量 = " . $count . "\n";
$count = time_complexity::logarithmic($n);
echo "对数阶（循环实现）的操作数量 = ".$count."\n";
$count = time_complexity::logRecur($n);
echo "对数阶（递归实现）的操作数量 = ".$count."\n";

$count = TimeComplexity::linearLogRecur($n);
echo "线性对数阶（递归实现）的操作数量 = " . $count . "\n";
$count = time_complexity::linearLogRecur($n);
echo "线性对数阶（递归实现）的操作数量 = ".$count."\n";

$count = TimeComplexity::factorialRecur($n);
echo "阶乘阶（递归实现）的操作数量 = " . $count . "\n";
$count = time_complexity::factorialRecur($n);
echo "阶乘阶（递归实现）的操作数量 = ".$count."\n";
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