【代码】
C++ Code
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/*
version: 1.0 author: hellogiser blog: http://www.cnblogs.com/hellogiser date: 2014/9/22 */ #include "stdafx.h" #include "iostream" #include <vector> using namespace std; void print(char *str) { cout << str << endl; } void swap(char *a, char *b) { char t = *a; *a = *b; *b = t; } //====================================================== // string permutation // abc =======abc,acb,bac,bca,cab,cba //====================================================== void permutation(char *str, int len, int index) { if (index == len) { print(str); } else { for (int i = index; i < len; i++) { swap(str[index], str[i]); permutation(str, len, index + 1); swap(str[index], str[i]); } } } void Permutation(char *str) { if(str == NULL || *str == ' ') return; int len = strlen(str); permutation(str, len, 0); } //====================================================== // string combination // abc =========a,b,c,ab,ac,bc,abc //====================================================== void print(vector<char> &result) { vector<char>::iterator iter = result.begin(); for (; iter != result.end(); iter++) { cout << *iter; } cout << endl; } void combination(char *str, int m, vector<char> &result) { // exception for example C(1,2) if(str == NULL || *str == ' ' && m > 0) return; //base cases if (m == 0) { print(result); return; } //choose current char C(n-1,m-1) result.push_back(*str); combination(str + 1, m - 1, result); // not choose current char C(n-1,m) result.pop_back(); combination(str + 1, m, result); } void Combination(char *str) { if(str == NULL || *str == ' ') return; vector<char> result; int len = strlen(str); for (int i = 1; i <= len; i++) { combination(str, i, result); } } void test_permutation() { char str[] = "abc"; Permutation(str); } void test_combination() { char str[] = "abc"; Combination(str); } void test_main() { test_permutation(); cout << "========================== "; test_combination(); } int main(void) { test_main(); return 0; } /* abc acb bac bca cba cab ========================== a b c ab ac bc abc */ |