Write a function:

function solution(A);

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Assume that:

 N is an integer within the range [1..100,000];
 each element of array A is an integer within the range [−1,000,000..1,000,000].

Complexity:

 expected worst-case time complexity is O(N);
 expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified.

Solution \$O(n^2)\$:

function solution(A) {
 for (i = 1; i < 1000000; i++) {
 if(!A.includes(i)) return i;
 }
}

Write a function:

function solution(A);

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Assume that:

• N is an integer within the range [1..100,000]
• Each element of array A is an integer within the range [−1,000,000..1,000,000]

Complexity:

• Expected worst-case time complexity is \$O(N)\$
• Expected worst-case space complexity is \$O(N)\$, beyond input storage (not counting the storage required for input arguments)

Elements of input arrays can be modified.

Solution in \$O(n^2)\$:

function solution(A) {
 for (i = 1; i < 1000000; i++) {
 if(!A.includes(i)) return i;
 }
}

Question:

Write a function:

function solution(A);

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Assume that:

 N is an integer within the range [1..100,000];
 each element of array A is an integer within the range [−1,000,000..1,000,000].

Complexity:

 expected worst-case time complexity is O(N);
 expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified.

AnswerO(N**2):

function solution(A) {
 for (i = 1; i < 1000000; i++) {
 if(!A.includes(i)) return i;
 }
}

Write a function:

function solution(A);

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Assume that:

 N is an integer within the range [1..100,000];
 each element of array A is an integer within the range [−1,000,000..1,000,000].

Complexity:

 expected worst-case time complexity is O(N);
 expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified.

Solution \$O(n^2)\$:

function solution(A) {
 for (i = 1; i < 1000000; i++) {
 if(!A.includes(i)) return i;
 }
}