TikTok OA, All 4 Passed: Min in a Range, Sorting by Vowel Gap, Bouncing Diagonals, Subarrays with at Least k Fruit Pairs

Q1: Minimum inside an open range

Keep the elements with nRange[0] < x < nRange[1] and return the smallest; return 0 if none qualify.

def min_in_open_range(nums, n_range):
    lo, hi = n_range
    return min((x for x in nums if lo < x < hi), default=0)

Q2: Sort words by vowel gap

For each word, count its vowels v and compute |v − (word length − v)|. Sort by this gap ascending, breaking ties alphabetically.

def sort_by_vowel_gap(words):
    def gap(w):
        v = sum(ch in "aeiouAEIOU" for ch in w)
        return abs(v - (len(w) - v))
    return sorted(words, key=lambda w: (gap(w), w))

Q3: Sort by bouncing-diagonal weight

For each element in the first column, walk the bouncing diagonal from (r, 0) — the row at column c is abs(r − c) — and sum the values to get its weight. Then sort by (weight, value).

For the full approach and code, see TikTok 2027 Intern OA (10/2), question 3.

Q4: Count subarrays with at least k pairs of fruit

Use a sliding window that tracks each fruit's frequency along with the number of pairs, sum(freq // 2):

• Keep extending the right edge.
• While the window has at least k pairs, shrink from the left.
• Count every valid subarray ending at the current right edge.

from collections import defaultdict

def count_subarrays_with_k_pairs(fruits, k):
    freq, pairs, left, total = defaultdict(int), 0, 0, 0
    for x in fruits:
        freq[x] += 1
        if freq[x] % 2 == 0:
            pairs += 1                     # a new pair is formed
        while pairs >= k:                  # [left..right] is valid; move left forward
            y = fruits[left]
            if freq[y] % 2 == 0:
                pairs -= 1
            freq[y] -= 1
            left += 1
        total += left                      # every start in 0..left-1 is valid
    return total

Time O(n). The key insight: growing the window can only add pairs, so validity is monotonic in the left edge — which is what makes two pointers work.