Recursion - All subsequences(output is not coming );

#1

#include<bits/stdc++.h>

using namespace std;

void all_subseq(string str,string ans)
{

if(str.length()==0){
 cout<<ans<endl;
    return;}

for(int i=0;i<str.length();i++)
{
	char ch=str[i];
	string ros=str.substr(i+1);
	all_subseq(ros,ans+ch);

}

}

int main()
{
int n;
cin>>n;
while(n>0)
{
string str;
cin>>str;
sort(str.begin(),str.end());
all_subseq(str,"");
n–;
}

return 0;

}

#2

hi sachin
there is no loop required in the recursive function and there is no need to sort the string also.
char ch=str[0];
string ros=str.substr(1);
print(ros,ans+ch); // include the current char
print(ros,ans); // do not include move forward

1 Like
#3

the output is not in lexicographical order.

#4

we need to print subsequences in lexicographical order

#5

can you please provide the exact question.

#6

Recursion - All subsequences
Print all the subsequences of a string in lexicographical order.

Input Format:
First line contains an integer N, the no of strings.
Next, N lines follows one string per line.
Constraints:
1 < len(str) < 20
Output Format:
No of subsequences one per line

Sample Input:
1
ab
Sample Output:

a
ab
b
Explanation:
4 subsequences are printed.
Empty string is a subsequence.

#7

yes for the lexographical order you need to sort the array at the end

#8

#include
#include
using namespace std;

void all_subseq(string str,string ans)
{

if(str.length()==0){
     cout<<ans<<endl;
	return;}

	char ch=str[0];
	string ros=str.substr(1);
	all_subseq(ros,ans+ch);
	all_subseq(ros,ans);

}

int main()
{
int n;
cin>>n;
while(n>0)
{
string str;
cin>>str;
sort(str.begin(),str.end());
all_subseq(str,"");
n–;
}

return 0;

}

#9

the output of this code is
1
ab
ab
a
b

#10

input

1
ab
output
ab
a
b

#11

the output is coming is wrong

#12

for the lexographical order you need to write your own compare function in the sort function that would sort it lexographically

#13

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1 Like