2025-10-14 Daily Challenge

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In: DailyChallenge

Today I have done leetcode's October LeetCoding Challenge with cpp.

October LeetCoding Challenge 14

Description

Adjacent Increasing Subarrays Detection I

Given an array nums of n integers and an integer k, determine whether there exist two adjacent subarrays of length k such that both subarrays are strictly increasing. Specifically, check if there are two subarrays starting at indices a and b (a < b), where:

  • Both subarrays nums[a..a + k - 1] and nums[b..b + k - 1] are strictly increasing.
  • The subarrays must be adjacent, meaning b = a + k.

Return true if it is possible to find two such subarrays, and false otherwise.

 

Example 1:

Input: nums = [2,5,7,8,9,2,3,4,3,1], k = 3

Output: true

Explanation:

  • The subarray starting at index 2 is [7, 8, 9], which is strictly increasing.
  • The subarray starting at index 5 is [2, 3, 4], which is also strictly increasing.
  • These two subarrays are adjacent, so the result is true.

Example 2:

Input: nums = [1,2,3,4,4,4,4,5,6,7], k = 5

Output: false

 

Constraints:

  • 2 <= nums.length <= 100
  • 1 < 2 * k <= nums.length
  • -1000 <= nums[i] <= 1000

Solution

class Solution {
public:
  bool hasIncreasingSubarrays(vector<int>& nums, int k) {
    if(k == 1) return true;
    int prev = 0;
    int increase = 1;
    int len = nums.size();
    for(int i = 1; i < len; ++i) {
      if(nums[i] > nums[i - 1]) {
        increase += 1;
        if(increase == k && prev >= k) return true;
        if(increase >= 2 * k) return true;
        continue;
      }
      prev = increase;
      increase = 1;
    }
    return false;
  }
};

// Accepted
// 1422/1422 cases passed (11 ms)
// Your runtime beats 76.82 % of cpp submissions
// Your memory usage beats 54.55 % of cpp submissions (40.5 MB)
Algorithm