function array_contain_consecutive_integers($arr) {
if (count($arr) <= 1) {
return true;
}
$min = $arr[0];
$max = $arr[0];
foreach ($arr as $val) {
if ($val < $min) {
$min = $val;
}
if ($val > $max) {
$max = $val;
}
}
if ($max - $min != count($arr) - 1) {
return false;
}
$st = array();
foreach ($arr as $val) {
if (in_array($val, $st)) {
return false;
}
(!in_array($val,$st) ? array_unshift($st, $val) : 0);
}
return true;
}
$arr = array(-2, 3, 0, -1, 4, 2, 1);
if (array_contain_consecutive_integers($arr)) {
echo "Yes";
}
else {
echo "No";
}
/*
run:
Yes
*/