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PHP winning probability algorithm, can be used for scratch card, large turntable lottery algorithm. The usage is very simple, there are detailed comments in the code, you can understand


<!--?</span--> PHP
/ *
* classical probability algorithms,
* $proArr is a preset array,
* array(100,200,300,400),
* start by screening if the first number is within the probability range of 1,1000,
* if not, then the probability space, which is the value of k minus the probability space of that number,
* in this case, it's minus 100, which means the second number is filtered in the range of 1,900.
* in this way, in the end, there will always be a number that meets the requirements.
* is the equivalent of going into a box to touch something,
* the first one is not, the second one is not, the third one is not, then the last one must be.
* this algorithm is simple and very efficient,
* the point is that this algorithm has been used in our previous projects, especially in projects with large data volumes.
* /
The function get_rand ($proArr) {
$result = ' ';
The total probability precision of a probability array
$proSum = array_sum ($proArr);
// probability array loop
Foreach ($proArr as $key = > $proCur) {
$randNum = mt_rand (1, $proSum);
If ($randNum < = ${proCur)
$result = $key;
Break;
} else {
$proSum - = $proCur;
}
}
The unset ($proArr);
Return the $result;
}


/ *
* awards array
* is a two-dimensional array that records all the prize information of the lottery.
* where id represents the winning grade, prize represents the prize, and v represents the probability of winning.
* note that the v must be an integer. You can set the v of the corresponding prize to 0, which means the probability of winning the prize is 0.
* the sum of v in the array (cardinality). The larger the cardinality, the more accurate the probability.
* the sum of v in this example is 100, so the probability of winning the lottery for a tablet is 1%.
* if the sum of v is 10,000, then the probability of winning is one in 10,000.
*
* /
$prize_arr = array (
'0' => array('id'=>1,'prize'=>' tablet ','v'=>1),
Array ('id'=>2,'prize'=>' digital camera ','v'=>5),
Array ('id'=>3,'prize'=>' speaker device ','v'=>10),
Array ('id'=>4,'prize'=>'4G usb drive ','v'=>12),
Array ('id'=>5,'prize'=>'10Q COINS ','v'=>22),
'5' = > array (' id '= > 6,' prize '= >' in the next time maybe you can oh ', 'v' = > 50).
);

/ *
* each request to the front page, the PHP loop awards set array,
* get the prize id of the draw through the probability calculation function get_rand.
* save the winning prize in the array $res['yes'],
* the rest of the unsuccessful winners are saved in $res['no'],
* finally, output json data to the front page.
* /
Foreach ($prize_arr as $key => $val) {
$arr [$val [' id ']] = $val [' v '];
}
$rids = get_rand ($arr); // get the award id according to the probability

$res [' yes'] = $prize_arr [$rids - 1] [' prize ']. / / in the awards
The unset ($prize_arr [$rids - 1)); // remove the winning entries from the array, leaving the missing entries
The shuffle ($prize_arr); // shuffle the array
For ($I = 0; $I < count ($prize_arr); ${i++)
$[] pr = $prize_arr [$I] [' prize '];
}
$res [' no '] = $pr;
Print_r ($res);
? >

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Copyright notice: this is an original article BY CSDN blogger "cyber swordsman". CC 4.0 by-sa copyright agreement is followed.
The original link: https://blog.csdn.net/dongsg11200/article/details/24607877