<?php

$Humans = 7000000000;
$EnabledZombies = 1;
$DisabledZombies = 0;
$DeadZombies = 0;
$AttacksAfterLastDisable = 0;
$Hour = 0;


function Attack($Rate, $ZombieSurviveRatio = 1) {

  global $Hour, $EnabledZombies, $DisabledZombies, $DeadZombies, $Humans, $AttacksAfterLastDisable;

  // We asume if a zomie is killed, that it doesn't infect a human.

  $ZombieDeadCount = ceil($EnabledZombies * (1 - $ZombieSurviveRatio));

  $DeadZombies += $ZombieDeadCount;
  $EnabledZombies -= $ZombieDeadCount;

  $ZombieAttacks = $EnabledZombies * $Rate;

  $Humans -= $ZombieAttacks;
  $EnabledZombies += $ZombieAttacks;

  $AttacksAfterLastDisable += $ZombieAttacks;
  $ZombieFallout = floor($AttacksAfterLastDisable / 5);
  $AttacksAfterLastDisable = $AttacksAfterLastDisable % 5;

  $EnabledZombies -= $ZombieFallout;
  $DisabledZombies += $ZombieFallout;

  echo "Hour: " . $Hour . ", Humans: " . $Humans . ", EnabledZombies: " . $EnabledZombies . ", DisabledZombies: " . $DisabledZombies . ", DeadZombies: " . $DeadZombies . "\n";

}


// First 8 Hour starting from 00.00 (so 1 per hour)

for ($i = 0; $i < 8; ++$i) {

  Attack(1, 1);

  ++$Hour;

}


while ($Humans > 0 ) {

  $DayHour = $Hour % 24;

  $AttackRate = $DayHour > 8 && $DayHour <= 22 ? 2 : 1;

  Attack($AttackRate , 0.66666666);

  ++$Hour;

}

echo "Total: " . ($EnabledZombies + $DisabledZombies + $DeadZombies + $Humans) . "\n";

?>

Hour: 0, Humans: 6999999999, EnabledZombies: 2, DisabledZombies: 0, DeadZombies: 0
Hour: 1, Humans: 6999999997, EnabledZombies: 4, DisabledZombies: 0, DeadZombies: 0
Hour: 2, Humans: 6999999993, EnabledZombies: 7, DisabledZombies: 1, DeadZombies: 0
Hour: 3, Humans: 6999999986, EnabledZombies: 13, DisabledZombies: 2, DeadZombies: 0
Hour: 4, Humans: 6999999973, EnabledZombies: 23, DisabledZombies: 5, DeadZombies: 0
Hour: 5, Humans: 6999999950, EnabledZombies: 41, DisabledZombies: 10, DeadZombies: 0
Hour: 6, Humans: 6999999909, EnabledZombies: 74, DisabledZombies: 18, DeadZombies: 0
Hour: 7, Humans: 6999999835, EnabledZombies: 133, DisabledZombies: 33, DeadZombies: 0
Hour: 8, Humans: 6999999747, EnabledZombies: 159, DisabledZombies: 50, DeadZombies: 45
Hour: 9, Humans: 6999999537, EnabledZombies: 273, DisabledZombies: 92, DeadZombies: 99
Hour: 10, Humans: 6999999175, EnabledZombies: 470, DisabledZombies: 165, DeadZombies: 191
Hour: 11, Humans: 6999998549, EnabledZombies: 814, DisabledZombies: 290, DeadZombies: 348
Hour: 12, Humans: 6999997465, EnabledZombies: 1409, DisabledZombies: 507, DeadZombies: 620
Hour: 13, Humans: 6999995587, EnabledZombies: 2442, DisabledZombies: 882, DeadZombies: 1090
Hour: 14, Humans: 6999992333, EnabledZombies: 4230, DisabledZombies: 1533, DeadZombies: 1905
Hour: 15, Humans: 6999986695, EnabledZombies: 7329, DisabledZombies: 2661, DeadZombies: 3316
Hour: 16, Humans: 6999976925, EnabledZombies: 12701, DisabledZombies: 4615, DeadZombies: 5760
Hour: 17, Humans: 6999959991, EnabledZombies: 22015, DisabledZombies: 8001, DeadZombies: 9994
Hour: 18, Humans: 6999930639, EnabledZombies: 38157, DisabledZombies: 13872, DeadZombies: 17333
Hour: 19, Humans: 6999879765, EnabledZombies: 66136, DisabledZombies: 24047, DeadZombies: 30053
Hour: 20, Humans: 6999791585, EnabledZombies: 114634, DisabledZombies: 41683, DeadZombies: 52099
Hour: 21, Humans: 6999638741, EnabledZombies: 198698, DisabledZombies: 72251, DeadZombies: 90311
Hour: 22, Humans: 6999373811, EnabledZombies: 344409, DisabledZombies: 125237, DeadZombies: 156544
Hour: 23, Humans: 6999144206, EnabledZombies: 413289, DisabledZombies: 171158, DeadZombies: 271348
Hour: 24, Humans: 6998868681, EnabledZombies: 495945, DisabledZombies: 226263, DeadZombies: 409112
Hour: 25, Humans: 6998538052, EnabledZombies: 595132, DisabledZombies: 292389, DeadZombies: 574428
Hour: 26, Humans: 6998141298, EnabledZombies: 714157, DisabledZombies: 371740, DeadZombies: 772806
Hour: 27, Humans: 6997665194, EnabledZombies: 856987, DisabledZombies: 466961, DeadZombies: 1010859
Hour: 28, Humans: 6997093870, EnabledZombies: 1028383, DisabledZombies: 581226, DeadZombies: 1296522
Hour: 29, Humans: 6996408282, EnabledZombies: 1234059, DisabledZombies: 718343, DeadZombies: 1639317
Hour: 30, Humans: 6995585577, EnabledZombies: 1480869, DisabledZombies: 882884, DeadZombies: 2050671
Hour: 31, Humans: 6994598332, EnabledZombies: 1777041, DisabledZombies: 1080333, DeadZombies: 2544295
Hour: 32, Humans: 6993413639, EnabledZombies: 2132447, DisabledZombies: 1317272, DeadZombies: 3136643
Hour: 33, Humans: 6990570377, EnabledZombies: 3696241, DisabledZombies: 1885924, DeadZombies: 3847459
Hour: 34, Humans: 6985642057, EnabledZombies: 6406816, DisabledZombies: 2871588, DeadZombies: 5079540
Hour: 35, Humans: 6977099637, EnabledZombies: 11105146, DisabledZombies: 4580072, DeadZombies: 7215146
Hour: 36, Humans: 6962292777, EnabledZombies: 19248918, DisabledZombies: 7541444, DeadZombies: 10916862
Hour: 37, Humans: 6936627555, EnabledZombies: 33364788, DisabledZombies: 12674489, DeadZombies: 17333169
Hour: 38, Humans: 6892141173, EnabledZombies: 57832297, DisabledZombies: 21571765, DeadZombies: 28454766
Hour: 39, Humans: 6815031445, EnabledZombies: 100242646, DisabledZombies: 36993711, DeadZombies: 47732199
Hour: 40, Humans: 6681374587, EnabledZombies: 173753916, DisabledZombies: 63725082, DeadZombies: 81146416
Hour: 41, Humans: 6449702703, EnabledZombies: 301173449, DisabledZombies: 110059459, DeadZombies: 139064390
Hour: 42, Humans: 6048138109, EnabledZombies: 522033972, DisabledZombies: 190372378, DeadZombies: 239455542
Hour: 43, Humans: 5352092821, EnabledZombies: 904858875, DisabledZombies: 329581435, DeadZombies: 413466870
Hour: 44, Humans: 4145614335, EnabledZombies: 1568422031, DisabledZombies: 570877133, DeadZombies: 715086502
Hour: 45, Humans: 2054384983, EnabledZombies: 2718598158, DisabledZombies: 989123003, DeadZombies: 1237893857
Hour: 46, Humans: -1570412523, EnabledZombies: 4712236758, DisabledZombies: 1714082504, DeadZombies: 2144093262
Total: 7000000001