A simple lottery probability function

A simple lottery probability function

Absrtact: This function is mainly to determine the probability range of the random number generated ...

A simple lottery probability function:

/** *  Simple lottery probability function  *  @param  array  $rewardArray   probability, such as: $rewardArray  =  Array (10, 20, 20, 30, 10, 10), corresponding to the probability of each prize  *  @return  int      Subscript for probability array  */function luckdraw ($rewardArray) {$sum  = array_sum ($rewardArray); if ($sum  !== 100) {return  ' error:the sum of values in  $rewardArray  must  be equal to 100! ';} Get random number $rewardnum = mt_rand (0,  $sum  - 1); $totalnum  = count ($rewardArray); For ($i  = 0;  $i  <  $totalnum;  $i + +) {if ($i  == 0) {if ($rewardArray [$i]  >  $rewardNum  &&  $rewardNum  >= 0) {return  $i;}} else{$max  =  $min  = 0;for ($j  = 0;  $j  <=  $i;  $j + +) {$max  =  $max  +  $rewardArray [$j];} For ($k  = 0;  $k  <  $i;  $k + +) {$min =  $min  +  $rewardArray [$k];} if ($max  >  $rewardNum  &&  $rewardNum  >=  $min) {return  $i;}}}

This function is mainly to determine the probability range of the random number generated.

Example:

$rewardArray = Array (10, 20, 20, 30, 10, 10);//each probability corresponds to a range of values//10,:0-10//20:10-30//20:30-50//30:50-80//10:80-90// 10:90-100echo Luckdraw ($rewardArray);

A simple lottery probability function