Maximum points you can obtain from cards

Array Sliding Window Prefix Sum

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Feb 25, 2026

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There are several cards arranged in a row, and each card has an associated number of points. The points are given in the integer array cardPoints. In one step, you can take one card from the beginning or from the end of the row. You have to take exactly k cards. Your score is the sum of the points of the cards you have taken. Given the integer array cardPoints and the integer k, return the maximum score you can obtain.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn max_score(card_points: Vec<i32>, k: i32) -> i32 {
    let n = card_points.len();
    let k = k as usize;
    let total: i32 = card_points.iter().sum();
    let window = n - k;
    // minimize the sum of the middle window of size 'window'
    let mut win_sum: i32 = card_points[..window].iter().sum();
    let mut min_win = win_sum;
    for i in window..n {
      win_sum += card_points[i] - card_points[i - window];
      min_win = min_win.min(win_sum);
    }
    total - min_win
  }
}