README.md

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

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

Solutions (Rust)

1. Solution

use std::collections::HashSet;

impl Solution {
    pub fn max_count(banned: Vec<i32>, n: i32, max_sum: i32) -> i32 {
        let banned = banned.into_iter().collect::<HashSet<_>>();
        let mut sum = 0;
        let mut ret = 0;

        for x in 1..=n {
            if !banned.contains(&x) && sum + x <= max_sum {
                sum += x;
                ret += 1;
            } else if sum + x > max_sum {
                break;
            }
        }

        ret
    }
}