find-the-most-competitive-subsequence.java

class Solution {
  public int[] mostCompetitive(int[] nums, int k) {
    Stack<Integer> stack = new Stack<>();
    for (int i = 0; i < nums.length; i++) {
      while (!stack.empty() && stack.peek() > nums[i] && k < stack.size() + nums.length - i) {
        stack.pop();
      }
      if (stack.size() < k) {
        stack.push(nums[i]);
      }
    }

    int[] arr = new int[stack.size()];

    for (int i = k - 1; i >= 0; i--) {
      arr[i] = stack.pop();
    }

    return arr;
  }
}