BFS+Hash(储存，判重) HDOJ 1067 Gap

#include <bits/stdc++.h>
using namespace std;

const int MOD = 1e6 + 7;
struct Point	{
int ch[5][9];
int x[4], y[4];
int step;
};
bool vis[MOD];
int ha;

int get_hash(int c[5][9])	{
int tmp[60], k = 0;
for (int i=1; i<=4; ++i)	{
for (int j=2; j<=8; ++j)	{
tmp[k++] = c[i][j] % 10;
tmp[k++] = c[i][j] / 10;
}
}
int ret = 0;
for (int i=0; i<k; ++i)	{
ret = (ret * 7 % MOD + tmp[i]) % MOD;
}
ret = (ret & 0x7fffffff) % MOD;
return ret;
}

int init(void)	{
int res[5][9];
int x[4] = {11, 21, 31, 41};
for (int i=0; i<4; ++i)	{
for (int j=1; j<=7; ++j)	{
res[i+1][j] = x[i]++;
}
res[i+1][8] = 0;
}
return get_hash (res);
}

void change(Point &v, int x0, int y0, int k)	{
int a = v.ch[x0][y0-1] + 1;
for (int i=1; i<=4; ++i)	{
for (int j=2; j<=8; ++j)	{
if (v.ch[i][j] == a)	{
v.x[k] = i;	v.y[k] = j;
swap (v.ch[x0][y0], v.ch[i][j]);
return ;
}
}
}
}

int BFS(Point &p)	{
memset (vis, false, sizeof (vis));
int sh = get_hash (p.ch);
vis[sh] = true;
queue<Point> que;	que.push (p);
while (!que.empty ())	{
Point u = que.front ();	que.pop ();
int uh = get_hash (u.ch);
if (uh == ha)	{
return u.step;
}
for (int i=0; i<4; ++i)	{
int x = u.x[i], y = u.y[i];
if (y == 1 || u.ch[x][y] % 10 == 7)	continue;
Point v = u;
change (v, x, y, i);
int vh = get_hash (v.ch);
if (vis[vh])	continue;
vis[vh] = true;	v.step++;
que.push (v);
}
}

return -1;
}

int main(void)	{
ha = init ();
int T;	scanf ("%d", &T);
while (T--)	{
Point p;	p.step = 0;
for (int i=1; i<=4; ++i)	{
p.ch[i][1] = 0;
}
for (int i=1; i<=4; ++i)	{
for (int j=2; j<=8; ++j)	{
scanf ("%d", &p.ch[i][j]);
}
}
for (int i=1; i<=4; ++i)	{
for (int j=2; j<=8; ++j)	{
if (p.ch[i][j] == 11)	{
swap (p.ch[1][1], p.ch[i][j]);
p.x[0] = i;	p.y[0] = j;
}
else if (p.ch[i][j] == 21)	{
swap (p.ch[2][1], p.ch[i][j]);
p.x[1] = i;	p.y[1] = j;
}
else if (p.ch[i][j] == 31)	{
swap (p.ch[3][1], p.ch[i][j]);
p.x[2] = i;	p.y[2] = j;
}
else if (p.ch[i][j] == 41)	{
swap (p.ch[4][1], p.ch[i][j]);
p.x[3] = i;	p.y[3] = j;
}
}
}
int ans = BFS (p);
printf ("%d\n", ans);
}

return 0;
}