从1-10开始，找到下一个缺失的数字？ [关闭]

Question

Say i have the following array: 1,2,3,6,8

I need to find that the next missing number is 4

What is the easiest and quickest way to perform this ?

Answer 1

Iterating the array and checking in_array() should do it.

$missing = null;

for ($i = 1; $i <= 10; $i++) {
    if (!in_array($i, $myArray)) {
        $missing = $i;
        break;
    }
}

if (!is_null($missing)) {
    // hit
}