2554. Maximum Number of Integers to Choose From a Range I

Problem

You are given an integer array banned and two integers n and maxSum. You are choosing some number of integers following the below rules:

• The chosen integers have to be in the range [1, n].

• Each integer can be chosen at most once.

• The chosen integers should not be in the array banned.

• The sum of the chosen integers should not exceed maxSum.

Return **the *maximum* number of integers you can choose following the mentioned rules**.

  Example 1:

Input: banned = [1,6,5], n = 5, maxSum = 6
Output: 2
Explanation: You can choose the integers 2 and 4.
2 and 4 are from the range [1, 5], both did not appear in banned, and their sum is 6, which did not exceed maxSum.

Example 2:

Input: banned = [1,2,3,4,5,6,7], n = 8, maxSum = 1
Output: 0
Explanation: You cannot choose any integer while following the mentioned conditions.

Example 3:

Input: banned = [11], n = 7, maxSum = 50
Output: 7
Explanation: You can choose the integers 1, 2, 3, 4, 5, 6, and 7.
They are from the range [1, 7], all did not appear in banned, and their sum is 28, which did not exceed maxSum.

  Constraints:

• 1 <= banned.length <= 104

• 1 <= banned[i], n <= 104

• 1 <= maxSum <= 109

Solution (Java)

class Solution {
    public int maxCount(int[] banned, int n, int maxSum) {
        HashSet<Integer> set = new HashSet<>();
        for(int ele : banned){
            set.add(ele);
        }

        int count = 0;
        for (int i = 1; i <= n; i++) {
            if (set.contains(i))
                continue;
            if (i <= maxSum) {
                count++;
                maxSum -= i;
            } else {
                break;
            }
        }
        return count;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).