Числа от 1 до 100 лежат в массиве, они хаотично перемешанные

Дан массив чисел, заполненный числами от 1 до 100. В нём не хватает одного числа из этой последовательности (1, ...,100). Необходимо найти это число. Алгоритм не должен превышать O(n^2) сложности.

Примеры:

searchDeleteNumber([
  1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
  23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41,
  42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60,
  61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
  80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 99,
  100
]) === 98

searchDeleteNumber([
    10, 11, 12, 13, 14, 1, 2, 3, 4, 5, 6, 7, 8, 9, 24, 25, 26, 27, 28, 29, 15,
    16, 17, 18, 19, 20, 21, 22, 23, 30, 31, 32, 33, 34, 35, 46, 47, 48, 49, 50,
    51, 52, 36, 38, 39, 40, 41, 42, 43, 44, 45, 53, 67, 68, 69, 70, 71, 72, 54,
    55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 73, 74, 75, 76, 77, 78, 92,
    93, 94, 95, 96, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 97, 98,
    99, 100
]) === 37

searchDeleteNumber([
  1, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 2, 3, 4, 5, 6, 7, 9, 10,
  11, 12, 13, 14, 15, 16, 17, 18, 19, 32, 47, 48, 49, 50, 51, 52, 53, 54, 55,
  56, 57, 58, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 59, 60,
  61, 62, 63, 64, 65, 66, 67, 68, 80, 81, 82, 83, 84, 85, 69, 70, 71, 72, 73,
  74, 75, 76, 77, 78, 79, 86, 87, 88, 91, 92, 93, 94, 95, 96, 97, 98, 89, 90,
  99, 100
]) === 8

searchDeleteNumber([
  16, 17, 18, 19, 20, 21, 22, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
  23, 36, 37, 38, 39, 40, 41, 42, 43, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
  34, 35, 44, 45, 46, 47, 48, 49, 50, 51, 64, 65, 66, 67, 69, 70, 52, 53, 54,
  55, 56, 57, 58, 59, 81, 82, 83, 84, 85, 86, 60, 61, 62, 63, 88, 89, 90, 91,
  92, 93, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 87, 94, 95, 99, 96, 97, 98,
  100
]) === 68

searchDeleteNumber([
  2, 3, 4, 17, 18, 19, 20, 21, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 22,
  23, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 24, 25,
  26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 54, 55, 68, 69, 70, 71, 72,
  73, 74, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 75, 76, 77, 78, 79,
  91, 92, 93, 94, 95, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 96, 97, 98,
  99, 100
]) === 1

Числа от 1 до 100 находятся в массиве, они хаотично перемешанные, но в нём не хватает одного числа из этой последовательности. Необходимо найти его