C 排列字母
我有2个字母p和C,N-迭代数(偶数)C 排列字母,c,recursion,permutation,C,Recursion,Permutation,我有2个字母p和C,N-迭代数(偶数) 例如,如果N=4=>联合循环发电厂、联合循环发电厂、联合循环发电厂、联合循环发电厂、联合循环发电厂、联合循环发电厂(其目的是展示这种解决方案,其中N=C-s的数量=P-s的数量)您可以生成置换 int N; cin >> N; string str = string(N/2, 'C') + string(N/2, 'P'); do { cout << str << endl; } while( next_perm
例如,如果N=4=>联合循环发电厂、联合循环发电厂、联合循环发电厂、联合循环发电厂、联合循环发电厂、联合循环发电厂(其目的是展示这种解决方案,其中N=C-s的数量=P-s的数量)
您可以生成置换
int N;
cin >> N;
string str = string(N/2, 'C') + string(N/2, 'P');
do {
cout << str << endl;
} while( next_permutation(str.begin(), str.end()));
到目前为止,您尝试了什么?请只选择一种语言,解决方案将根据所选语言的不同而有所不同。您有问题吗?我如何用C实现这一点?请注意,将
'C'
放在'P'
之前很重要,因为str
应该排序以迭代所有排列。对于C
,您需要在下一次置换时编写函数。只要有时间,我就会更新答案。@Jarod42你说得对。我从页面中链接的其他来源借用了该定义。该定义似乎仅适用于长度不超过3的字符串。我会用我自己的定义来代替,我错了很久了,它的灵感来自stl算法。
typedef int bool;
bool true = 1;
bool false = 0;
int compare (const void *a, const void * b)
{ return ( *(char *)a - *(char *)b ); }
void swap (char* a, char* b)
{
char t = *a;
*a = *b;
*b = t;
}
// This function finds the index of the smallest character
// which is greater than 'first' and is present in str[l..h]
int findCeil (char str[], char first, int l, int h)
{
// initialize index of ceiling element
int ceilIndex = l, i;
// Now iterate through rest of the elements and find
// the smallest character greater than 'first'
for (i = l+1; i <= h; i++)
if (str[i] > first && str[i] < str[ceilIndex])
ceilIndex = i;
return ceilIndex;
}
// Print all permutations of str in sorted order
void permute ( char str[] )
{
// Get size of string
int size = strlen(str);
// Print permutations one by one
bool isFinished = false;
while ( ! isFinished )
{
int i;
// print this permutation
printf ("%s \n", str);
// Find the rightmost character which is smaller than its next
// character. Let us call it 'first char'
for ( i = size - 2; i >= 0; --i )
if (str[i] < str[i+1])
break;
// If there is no such chracter, all are sorted in decreasing order,
// means we just printed the last permutation and we are done.
if ( i == -1 )
isFinished = true;
else
{
// Find the ceil of 'first char' in right of first character.
// Ceil of a character is the smallest character greater than it
int ceilIndex = findCeil( str, str[i], i + 1, size - 1 );
// Swap first and second characters
swap( &str[i], &str[ceilIndex] );
// Sort the string on right of 'first char'
qsort( str + i + 1, size - i - 1, sizeof(str[0]), compare );
}
}
}
int main(void) {
int N;
char *a = NULL;
if(1 != scanf("%d\n", &N)) {
fprintf(stderr, "Can not read the value of N\n");
return 1;
}
a = malloc(N + 1);
if(!a) {
fprintf(stderr, "Out of mem\n");
return 1;
}
memset(a, 'C', N/2);
memset(a + N/2, 'P', N/2);
a[N] = '\0';
permute(a, 0, strlen(a) - 1);
free(a);
return 0;
}