Question

16. String Subsequences

Given two strings, determine the number of times
the first one appears as a subsequence in the
second one. A subsequence is created by
eliminating any number of characters from a string
(possibly 0) without changing the order of the

characters retained.

For example, let's say s1 = "ABC" and s2=
"ABCBABC". The first string appears 5 times as a

Subsequence in the second string at 1-indexed
positions of (1, 2, 3), (1, 2, 7), (1,4, 7), (1. 6, 7), and (5,
6, 7). Therefore, the answer is 5.

Function Description
Complete the function getSubsequence Count in the

editor below.

getsubsequenceCount has the following

parameters:

string s1: the first string, which always has a
length of 3
string s2: the second string

Returns:

int: the number of times sl appears as a
subsequence in s22

Constraints

length.of si- a​
Sample Input For Custom Testing

Function

STDIN

HRW

s1 "HRW"

HERHRWS s2 "HERHRWS"

Sample Output

3

Explanation
"HRW appears as a subsequence in "HERHRWS"3
times at positions (1,3, 6), (1, 5, 6), and (4, 5, 6).
Therefore, the answer is 3.
Returns:

int: the number of times s1 appears as a
subsequence in s2

Constraints

length of s13

1s length of s2s 5*10
s1 and s2 consist of uppercase English
letters, asci[A-Z]

Input Format For Custom Testing

Sample Case 0

Sample Input For Custom Testing

STDIN

Function

HRW

S1 "HRW

HERHRWS s2 "HERHRWS"

Sample Output

Explanation
HRW appears as a subsequence in "HERHRWS" 3
times at positions (1, 3, 6), (1, 5, 6), and (4, 5, 6).
Therefore, the answer is 3.

Sample Case 1

Sample Input For Custom Testing

STDIN

Function

ELO

sl "ELO"

HELLOWORLD

s2"HELLOWORLD"

Sample Output

Explanation
ELO appears as a subsequence in
"HELLOWORLD" 4 times at positions (2, 3, 5), (2, 3,
7,2,4, 5), and (2, 4, 7). Therefore I​

Answer 1

Answer:

Given two strings, determine the number of times

the first one appears as a subsequence in the

second one. A subsequence is created by

eliminating any number of characters from a string

(possibly 0) without changing the order of the

characters retained.

For example, let's say s1 = "ABC" and s2=

"ABCBABC". The first string appears 5 times as a

Subsequence in the second string at 1-indexed

positions of (1, 2, 3), (1, 2, 7), (1,4, 7), (1. 6, 7), and (5,

6, 7). Therefore, the answer is 5.

Function Description

Complete the function getSubsequence Count in the

editor below.

getsubsequenceCount has the following

parameters:

string s1: the first string, which always has a

length of 3

string s2: the second string

Returns:

int: the number of times sl appears as a

subsequence in s22

Constraints

length.of si- a​

Sample Input For Custom Testing

Function

STDIN

HRW

s1 "HRW"

HERHRWS s2 "HERHRWS"

Sample Output

3

Explanation

"HRW appears as a subsequence in "HERHRWS"3

times at positions (1,3, 6), (1, 5, 6), and (4, 5, 6).

Therefore, the answer is 3.

Returns:

int: the number of times s1 appears as a

subsequence in s2

Constraints

length of s13

1s length of s2s 5*10

s1 and s2 consist of uppercase English

letters, asci[A-Z]

Input Format For Custom Testing

Sample Case 0

Sample Input For Custom Testing

STDIN

Function

HRW

S1 "HRW

HERHRWS s2 "HERHRWS"

Sample Output

Explanation

HRW appears as a subsequence in "HERHRWS" 3

times at positions (1, 3, 6), (1, 5, 6), and (4, 5, 6).

Therefore, the answer is 3.

Sample Case 1

Sample Input For Custom Testing

STDIN

Function

ELO

sl "ELO"

HELLOWORLD

s2"HELLOWORLD"

Sample Output

Explanation

ELO appears as a subsequence in

"HELLOWORLD" 4 times at positions (2, 3, 5), (2, 3,

7,2,4, 5), and (2, 4, 7). Therefore I​