https://leetcode.com/problems/find-the-prefix-common-array-of-two-arrays/description/


A[..i] and B[..i] intersections sizes #medium #counting

https://leetcode.com/problems/first-completely-painted-row-or-column/description/


Index of first filled row/column in 2D matrix #medium #counting

https://leetcode.com/problems/tuple-with-same-product/description/


Count uniq 4-tupples a*b=c*d #medium #counting #sort

https://leetcode.com/problems/count-number-of-bad-pairs/description/


Count pairs a[i] - a[j] != j - i #medium #counting #sorting

All numbers in pairs #easy #counting #sorting


https://leetcode.com/problems/divide-array-into-equal-pairs/description/

Min split index to have equal majority elements #medium #counting


https://leetcode.com/problems/minimum-index-of-a-valid-split/description/

# 30.06.2025
[594. Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence/description) easy


Longest subsequence with max-min=1 #easy #counting #sort #two_pointers

# 1.07.2025
[3330. Find the Original Typed String I](https://leetcode.com/problems/find-the-original-typed-string-i/description/) easy


ways to remove duplicates #easy #counting