原文:
给定一个字符串，我们必须找出它的所有子序列。字符串是给定字符串的子序列，它是通过删除给定字符串的某些字符而不改变其顺序来生成的。
示例:
input : abc
output : a, b, c, ab, bc, ac, abc
input : aaa
output : a, aa, aaa
方法 1(挑与不挑概念)
c
// c program for the above approach
#include
using namespace std;
// find all subsequences
void printsubsequence(string input, string output)
{
// base case
// if the input is empty print the output string
if (input.empty()) {
cout << output << endl;
return;
}
// output is passed with including
// the ist character of
// input string
printsubsequence(input.substr(1), output input[0]);
// output is passed without
// including the ist character
// of input string
printsubsequence(input.substr(1), output);
}
// driver code
int main()
{
// output is set to null before passing in as a
// parameter
string output = "";
string input = "abcd";
printsubsequence(input, output);
return 0;
}
java
// java program for the above approach
import java.util.*;
class gfg {
// declare a global list
static list al = new arraylist<>();
// creating a public static arraylist such that
// we can store values
// if there is any question of returning the
// we can directly return too// public static
// arraylist al = new arraylist();
public static void main(string[] args)
{
string s = "abcd";
findsubsequences(s, ""); // calling a function
system.out.println(al);
}
private static void findsubsequences(string s,
string ans)
{
if (s.length() == 0) {
al.add(ans);
return;
}
// we add adding 1st character in string
findsubsequences(s.substring(1), ans s.charat(0));
// not adding first character of the string
// because the concept of subsequence either
// character will present or not
findsubsequences(s.substring(1), ans);
}
}
python 3
# below is the implementation of the above approach
def printsubsequence(input, output):
# base case
# if the input is empty print the output string
if len(input) == 0:
print(output, end=' ')
return
# output is passed with including the
# 1st character of input string
printsubsequence(input[1:], output input[0])
# output is passed without including the
# 1st character of input string
printsubsequence(input[1:], output)
# driver code
# output is set to null before passing in
# as a parameter
output = ""
input = "abcd"
printsubsequence(input, output)
# this code is contributed by tharun reddy
c
// c# program for the above approach
using system;
using system.collections.generic;
class gfg{
static void printsubsequence(string input,
string output)
{
// base case
// if the input is empty print the output string
if (input.length == 0)
{
console.writeline(output);
return;
}
// output is passed with including
// the ist character of
// input string
printsubsequence(input.substring(1),
output input[0]);
// output is passed without
// including the ist character
// of input string
printsubsequence(input.substring(1),
output);
}
// driver code
static void main()
{
// output is set to null before passing
// in as a parameter
string output = "";
string input = "abcd";
printsubsequence(input, output);
}
}
// this code is contributed by soumikmondal
javascript
输出
abcd
abc
abd
ab
acd
ac
ad
a
bcd
bc
bd
b
cd
c
d
麻将胡了pg电子网站的版权属于：月萌api www.moonapi.com，转载请注明出处
