如何找到字符串的排列？

Question

如何找到特定字符串的组合......

ABCD - “”，A，B，C，AB，AC，AD，BC，BD，CD，ABC，ACD，ABD，ABCD，......

C编程语言....

感谢..

Answer 1

在set中插入您需要的字母并调用findSubset。

Set findSubsets(Set A)
{
     if A is the empty set
            return the empty set

     // The first element of our set is A[0]
     // (A - A[0] is the set A without the first element)
     Set B := findSubsets(A - A[0])

     // Set B is now all the subsets of A without the first element
     // We now find all the subsets of A containing the first element by finding
     // tacking on the first element to the sets inside B
     Set C = {}
     For each set D in B
            add {A[0], D} to C

    return B added to C
}

Answer 2

在python中，标准库ìtertools应该有所帮助。看看combinations()功能，也许还有其他功能，具体取决于您想要的 exacly 。你想允许重复吗？订单重要吗？