可以由给定的弦形成的任何长度的所有可能的弦
给定一串不同的字符，打印由给定字符串组成的任何长度的所有可能的字符串。
示例:
Input: abc
Output: a b c abc ab ac bc bac bca
cb ca ba cab cba acb
Input: abcd
Output: a b ab ba c ac ca bc cb abc acb bac
bca cab cba d ad da bd db abd adb bad
bda dab dba cd dc acd adc cad cda dac
dca bcd bdc cbd cdb dbc dcb abcd abdc
acbd acdb adbc adcb bacd badc bcad bcda
bdac bdca cabd cadb cbad cbda cdab cdba
dabc dacb dbac dbca dcab dcba
所有字符串的生成包括以下步骤。 1) 生成给定字符串的所有子序列。 2)对于每个子序列“子序列”，打印“子序列”的所有排列
下面是 C++实现。它使用 C++中的next _ 置换函数。
C/C++
/* C++ code to generate all possible strings
that can be formed from given string */
#include<bits/stdc++.h>
using namespace std;
void printAll(string str)
{
/* Number of subsequences is (2**n -1)*/
int n = str.length();
unsigned int opsize = pow(2, n);
/* Generate all subsequences of a given string.
using counter 000..1 to 111..1*/
for (int counter = 1; counter < opsize; counter++)
{
string subs = "";
for (int j = 0; j < n; j++)
{
/* Check if jth bit in the counter is set
If set then print jth element from arr[] */
if (counter & (1<<j))
subs.push_back(str[j]);
}
/* Print all permutations of current subsequence */
do
{
cout << subs << " ";
}
while (next_permutation(subs.begin(), subs.end()));
}
}
// Driver program
int main()
{
string str = "abc";
printSubsequences(str);
return 0;
}
版权属于：月萌API www.moonapi.com，转载请注明出处
