PHP full-arrangement algorithm implementation program code _ PHP Tutorial

PHP full sorting algorithm implements program code. PHP full sorting algorithm implements program code to take m (mn) elements from n different elements and arrange them in a certain order, it is called an arrangement for retrieving m elements from n different elements. When PHP fully-arranged algorithms implement program code

M (m ≤ n) elements from n different elements are arranged in a certain order, which is called an arrangement of m elements from n different elements. When m = n, all data is arranged in full order.

Introduction

For example, columns 1, 2, and 3 in the full row:

1, 2, 3

1, 3, 2

2, 1, 3

2, 3, 1

3, 1, 2

3, 2, 1

A total of 3*2*1 = 6 3!

2 Formula

Number of fully arranged items f (n) = n! (Definition 0! = 1)

Recursive Algorithms

1, 2, 3

1, 3, 2

2, 1, 3

2, 3, 1

3, 2, 1

3, 1, 2

This is because the algorithm only considers how to output a full arrangement, but does not consider whether there is a problem with the transposition. So I proposed a solution, which is to modify the transposition function.

For example, if you change the positions of 1 2 3, you should not directly change the positions of 3 2 1, so that 3 and 1 are directly changed. Instead, 3 is placed at the front and back, and 1 2 is placed backward.

Basic Algorithms

The following describes four full-rank algorithms:

(A) lexicographic method

(B) incremental carry-in method

(C) decimal carry-in method

(D) adjacent-position swap method

Implement a full sorting algorithm

The code is as follows:

Header ("content-type: text/html; charset = utf-8 ");/** * @ Param array $ a set of elements to be arranged, which dynamically changes * @ Param array $ B stores the current arrangement * @ Param array $ M the set of elements to be arranged. it is equivalent to a constant and always the set of elements to be sorted. */ Function wholerange ($ a, $ B, $ M ){ $ Range = array (); If (count ($ a)> 1 ){ $ D = $ B; Foreach ($ a as $ value ){ $ B [] = $ value; $ C = array_diff ($ M, $ B ); If (count ($ c)> 0 ){ $ Range [] = wholerange ($ c, $ B, $ M ); } $ B = $ d; } } Elseif (count ($ a) = 1 ){ Foreach ($ a as $ value ){ $ B [] = $ value; } $ Onerange = ""; Foreach ($ B as $ value ){ $ Onerange. = $ value; } $ Range [] = $ onerange; } Return $ range; } /** * Recursive output array * * @ Param array $ array to be output by arr * @ Return int returns the number of array elements */ Function recursionarray ($ arr ){ $ I = 0; Foreach ($ arr as $ value ){ If (is_array ($ value )){ $ I + = recursionarray ($ value ); } Else { Echo $ value ." "; $ I ++; } } Return $ I; } $ A = array ('A', 'B', 'C', 'D '); $ B = array (); $ Range = wholerange ($ a, $ B, $ ); $ Count = recursionarray ($ range ); Echo "a total of". $ count. "arrays "; ?>

A condition is an arrangement of m (mn) elements from n different elements in a certain order. it is called an arrangement of m elements from n different elements. When...