Search⌘ K
AI Features

Solution: Distinct Subsequences

Explore a dynamic programming method to determine the number of distinct subsequences in one string that match another exactly. This lesson guides you through a space-efficient solution using a 1D array and reverse iteration, helping you master a key algorithm pattern important for coding interviews.

Statement

Given two strings, s and t, determine how many distinct subsequences of s match t exactly.

Note: A subsequence is formed by deleting zero or more characters from s without changing the relative order of the remaining characters.

You may assume the result will always fit within a 3232-bit signed integer.

Constraints:

  • 11 \leq s.length, t.length 1000\leq 1000 ...