POJ3087 hash

这道题看别人用模拟做代码短，时间也快，我用hash做，纯粹只是为了练习，hash的确是不熟，还得多练练。

//47ms
#include <iostream>
using namespace std;
#define SIZE 102
#define TAB_SIZ 14997

int size;

struct ListNode
{
	char s[2*SIZE];
	struct ListNode *next;
};

struct ListNode *table[TAB_SIZ];

int Hash(char *key)
{
	unsigned int hashVal = 0, i;
	for(i = 0; i < 2*size; i++)
        hashVal = (hashVal << 5) + key[i];
	return hashVal % TAB_SIZ;
}

bool isFind(int key, char *b)
{
    struct ListNode *l, *p;
    bool flag = false;
    int i;
	
	l = table[key];
	p = l->next;
	while(p != NULL && !flag)
	{
        for(i = 0; i < 2*size; i++)
			if(b[i] != p->s[i])
				break;
			if(i == 2*size)
				flag = true;
			else
				p = p->next;
	}
//	cout << "flag " << flag << endl;
    return flag;
}

void Insert(int key, char *b)
{
	struct ListNode *newCell, *l;
	int i;
	
	newCell = (ListNode *)malloc(sizeof(ListNode));
	l = table[key];
	newCell->next = l->next;
	l->next = newCell;
	
	for(i = 0; i < 2*size; i++)
		newCell->s[i] = b[i];
}
void shuffle(char *s1, char *s2, char *tmp)
{
    int i;
	
	for(i = 0; i < size; i++)
	{
		tmp[2*i] = s2[i];
		tmp[2*i+1] = s1[i];
	}
	tmp[2*size] = '\0';
}
void split(char *s1, char *s2, char *tmp)
{
	int i;

	for(i = 0; i < 2*size; i++)
		if(i < size)
			s1[i] = tmp[i];
		else
			s2[i-size] = tmp[i];
	s1[size] = '\0';
	s2[size] = '\0';
}
int main()
{
	int cas, i, j = 1, dist;
    char s1[SIZE], s2[SIZE];
    char tmp[2*SIZE], target[2*SIZE];
	
   // freopen("a.txt", "r", stdin);

	for(i = 0; i < TAB_SIZ; i++)
	{
            table[i] = (struct ListNode *)malloc(sizeof(struct ListNode));
			table[i]->next = NULL;
	}
	cin >> cas;
	while(j <= cas)
	{
		for(i = 0; i < TAB_SIZ; i++)
			table[i]->next = NULL;
		dist = 0;
		cin >> size;
        cin >> s1 >> s2 >> target;
	//	cout << target << endl;
	//	cout << s1 << "  " << s2 << endl;
		cout << j << " ";
		while(true)
		{
			shuffle(s1, s2, tmp);
		//	cout << "tmp " << tmp << endl; 
			for(i = 0; i < 2*size; i++)
				if(target[i] != tmp[i])
					break;
			if(i == 2*size)
			{
				cout << dist+1 << endl;
				break;
			}
			else
			{
				int key = Hash(tmp);
				if(isFind(key, tmp))
				{
					cout << -1 << endl;
					break;
				}
				else
				{
					Insert(key, tmp);
					dist++;
				}
			}
			split(s1, s2, tmp);
			//	cout << s1 << "  " << s2 << endl;
		}
		j++;
	}
	return 0;
}