Detailed explanation of php WeChat red envelope random generation algorithm

function randBonus($bonus_total=0, $bonus_count=3, $bonus_type=1){ $bonus_items = array(); // 将要瓜分的结果 $bonus_balance = $bonus_total; // 每次分完之后的余额 $bonus_avg = number_format($bonus_total/$bonus_count, 2); // 平均每个红包多少钱 $i = 0; while($i<$bonus_count){ if($i<$bonus_count-1){ $rand = $bonus_type?(rand(1, $bonus_balance*100-1)/100):$bonus_avg; // 根据红包类型计算当前红包的金额 $bonus_items[] = $rand; $bonus_balance -= $rand; }else{ $bonus_items[] = $bonus_balance; // 最后一个红包直接承包最后所有的金额，保证发出的总金额正确 } $i++; } return $bonus_items; }

// 发3个拼手气红包，总金额是100元 $bonus_items = randBonus(100, 3, 1); // 查看生成的红包 var_dump($bonus_items); // 校验总金额是不是正确，看看微信有没有坑我们的钱 var_dump(array_sum($bonus_items));

function sendRandBonus($total=0, $count=3, $type=1){ if($type==1){ $input = range(0.01, $total, 0.01); if($count>1){ $rand_keys = (array) array_rand($input, $count-1); $last = 0; foreach($rand_keys as $i=>$key){ $current = $input[$key]-$last; $items[] = $current; $last = $input[$key]; } } $items[] = $total-array_sum($items); }else{ $avg = number_format($total/$count, 2); $i = 0; while($i<$count){ $items[] = $i<$count-1?$avg:($total-array_sum($items)); $i++; } } return $items; }