g0101_0200.s0115_distinct_subsequences

Class Solution

java.lang.Object

g0101_0200.s0115_distinct_subsequences.Solution

public class Solution
extends Object

115 - Distinct Subsequences.

Hard

Given two strings s and t, return the number of distinct subsequences of s which equals t.

A string’s subsequence is a new string formed from the original string by deleting some (can be none) of the characters without disturbing the remaining characters’ relative positions. (i.e., "ACE" is a subsequence of "ABCDE" while "AEC" is not).

It is guaranteed the answer fits on a 32-bit signed integer.

Example 1:

Input: s = “rabbbit”, t = “rabbit”

Output: 3

Explanation: As shown below, there are 3 ways you can generate “rabbit” from S. **rabb**b**it** **ra**b**bbit** **rab**b**bit**

Example 2:

Input: s = “babgbag”, t = “bag”

Output: 5

Explanation: As shown below, there are 5 ways you can generate “bag” from S. **ba**b**g**bag **ba**bgba**g** **b**abgb**ag** ba**b**gb**ag** babg**bag**

Constraints:

• 1 <= s.length, t.length <= 1000
• s and t consist of English letters.

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	numDistinct(String text, String text2)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

numDistinct

public int numDistinct(String text,
                       String text2)