Created
November 1, 2017 18:39
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Simple Algorigthm: Closest biggest adjacent number
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| <?php | |
| // By Carlos Gratacos | |
| // Input: 1 interger number | |
| // Output: false-> if not possible, else return return the smaller or greater input by switching adjacent digit | |
| // Biggest closest to the original one | |
| // 123 -> 132 | |
| // | |
| // 254 -> 524 | |
| // | |
| // 1653 -> (1635, 1653) -> 6135 | |
| // | |
| // 71132 -> 71312 | |
| // | |
| // 9876543210 -> false | |
| // | |
| function biggest(int $x) { | |
| $str_num = (string)$x; | |
| $biggest = rotation($str_num); | |
| return $biggest > $x ? $biggest: false; | |
| } | |
| // Rotate | |
| function rotation(string $num) { | |
| $arr = str_split($num); | |
| $stop = null; | |
| for($i = strlen($num)-1; $i > 0; $i-- ) { | |
| if ($arr[$i] > $arr[$i-1]) { | |
| $last = $arr[$i]; | |
| $arr[$i] = $arr[$i-1]; | |
| $arr[$i-1] = $last; | |
| $stop = $i; | |
| break; | |
| } | |
| } | |
| if(isset($stop)){ | |
| for($i = $stop; $i < strlen($num)-1; $i++ ) { | |
| if ($arr[$i] > $arr[$i+1]) { | |
| $last = $arr[$i]; | |
| $arr[$i] = $arr[$i+1]; | |
| $arr[$i+1] = $last; | |
| } | |
| } | |
| } | |
| return (int)implode('', $arr); | |
| } | |
| function test(){ | |
| $arr = [123,254, 1653, 0, 71132,45325, 9876543210]; | |
| foreach($arr as $val) { | |
| $x =biggest($val); | |
| echo $val." biggest number is " . ($x?:"None") . "<br>"; | |
| } | |
| } | |
| test(); |
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