[BZOJ2462] [BeiJing2011]矩阵模板（二维Hash）

传送门

二维哈希即可。

注意质数选的大一些，不然会超时。

还有插入的时候不判重居然比判重要快。。

——代码

#include <cstdio>
#include <cstring>
#include <iostream>
#define UI unsigned int

const int p = 1000007, MAXN = 1001;
int n, m, a, b, q, cnt, head
, next[MAXN * MAXN];
UI h, sum[MAXN][MAXN], base1[MAXN], base2[MAXN], to[MAXN * MAXN];

inline void insert(UI x)
{
int i, a = x % p;
for(i = head[a]; i ^ -1; i = next[i])
if(!(to[i] ^ x))
return;
to[cnt] = x;
next[cnt] = head[a];
head[a] = cnt++;
}

inline bool find(UI x)
{
int i, a = x % p;
for(i = head[a]; i ^ -1; i = next[i])
if(!(to[i] ^ x))
return 1;
return 0;
}

int main()
{
int i, j;
scanf("%d %d %d %d", &n, &m, &a, &b);
base1[0] = base2[0] = 1;
memset(head, -1, sizeof(head));
for(i = 1; i <= n; i++) base1[i] = base1[i - 1] * 19260817;
for(i = 1; i <= m; i++) base2[i] = base2[i - 1] * 20011001;
for(i = 1; i <= n; i++)
for(j = 1; j <= m; j++)
scanf("%1d", &sum[i][j]);
for(i = 1; i <= n; i++)
for(j = 1; j <= m; j++)
sum[i][j] += sum[i - 1][j] * 19260817;
for(i = 1; i <= n; i++)
for(j = 1; j <= m; j++)
sum[i][j] += sum[i][j - 1] * 20011001;
for(i = a; i <= n; i++)
for(j = b; j <= m; j++)
{
h = sum[i][j];
h -= sum[i - a][j] * base1[a];
h -= sum[i][j - b] * base2[b];
h += sum[i - a][j - b] * base1[a] * base2[b];
insert(h);
}
scanf("%d", &q);
while(q--)
{
for(i = 1; i <= a; i++)
for(j = 1; j <= b; j++)
scanf("%1d", &sum[i][j]);
for(i = 1; i <= a; i++)
for(j = 1; j <= b; j++)
sum[i][j] += sum[i - 1][j] * 19260817;
for(i = 1; i <= a; i++)
for(j = 1; j <= b; j++)
sum[i][j] += sum[i][j - 1] * 20011001;
printf("%d\n", find(sum[a][b]));
}
return 0;
}