2022-05-02：给定一个数组arr，一个正数num，一个正数k，可以把arr中的某些数字拿出来组成一组，要求该组中的最大值

fn main() {
    let mut arr: Vec<isize> = vec![1, 2, 3, 3, 3, 10, 10, 10, 100, 100, 100];
    let ans = max_teams2(&mut arr, 3, 3);
    println!("ans = {}", ans);
}

// 时间复杂度O(N * logN)
fn max_teams2(arr: &mut Vec<isize>, num: isize, k: isize) -> isize {
    let n: isize = arr.len() as isize;
    if k > n {
        return 0;
    }
    arr.sort_unstable();
    let mut dp: Vec<isize> = vec![];
    for _ in 0..n {
        dp.push(0);
    }
    dp[(k - 1) as usize] = if arr[(k - 1) as usize] - arr[0] <= num {
        1
    } else {
        0
    };
    for i in k..n {
        let p1 = dp[(i - 1) as usize];
        let p2 = if arr[i as usize] - arr[(i - k + 1) as usize] <= num {
            1
        } else {
            0
        } + dp[(i - k) as usize];
        dp[i as usize] = get_max(p1, p2);
    }
    return dp[(n - 1) as usize];
}

fn get_max(a: isize, b: isize) -> isize {
    if a > b {
        a
    } else {
        b
    }
}