#include<stdio.h>
#define Mod 1000000007
int w2,n,p,q,w,a[2010],b[2010],ch[2010][6],w1,same[2010],dif[2010],cnt2[2010];
long long invfact[4010],t,dap,cnt,d1[2010],d[2010],dif1[2010],dp[2010][2010],fact[4010];
char x2,c[7];
long long comb(int n,int r)
{
if(r==0) return 1;
long long s;
s=fact[n]*invfact[r]; s%=Mod;
s*=invfact[n-r]; s%=Mod;
return s;
}
long long pow(long long x,long long b)
{
long long c=x,ans=1;
while(b)
{
if(b%2) ans*=c;
b/=2; c*=c; c%=Mod; ans%=Mod;
}
return ans;
}
int main()
{
int i,j,x;
scanf("%d %d %d",&n,&p,&q); fact[0]=1; invfact[0]=1;
for(i=1;i<=4000;i++){fact[i]=fact[i-1]*i; fact[i]%=Mod;}
for(i=1;i<=4000;i++) invfact[i]=pow(fact[i],Mod-2);
for(i=1;i<=n;i++){
scanf(" %c",&x2);
a[i]=x2-'a'+1;
}
for(i=1;i<=n;i++){
scanf(" %c",&x2);
b[i]=x2-'a'+1;
}
for(i=1;i<=n;i++){
scanf("%s",&c);
for(j=0;j<=4;j++){
if(c[j]!='.') ch[i][j+1]=1, cnt2[i]++;
}
}
for(i=1;i<=n;i++){
if(a[i]==b[i]) same[++w]=i;
else{
if(ch[i][b[i]]) dif1[++w1]=cnt2[i]-2;
}
}
dp[0][0]=1;
for(i=1;i<=w;i++){
x=same[i]; cnt=0;
for(j=1;j<=5;j++){
if(ch[x][j]) cnt++;
}
if(ch[x][a[x]]) dp[i][0]=dp[i-1][0]*(cnt-1);
else dp[i][0]=dp[i-1][0]*cnt;
dp[i][0]%=Mod;
for(j=1;j<=i;j++){
if(ch[x][a[x]]) dp[i][j]=dp[i-1][j-1]+dp[i-1][j]*(cnt-1);
else dp[i][j]=dp[i-1][j]*cnt;
dp[i][j]%=Mod;
}
}
for(i=0;i<=w;i++) d[i]=dp[w][i];
for(i=1;i<=w1;i++)
{
dp[i][0]=dp[i-1][0]*dif1[i]; dp[i][0]%=Mod;
for(j=1;j<=i;j++)
{
dp[i][j]=dp[i-1][j]*dif1[i]+dp[i-1][j-1];
dp[i][j]%=Mod;
}
}
for(i=0;i<=w1;i++) d1[i]=dp[w1][i];
for(i=0;i<=p && i<=q;i++)
{
if(p+q-i*2<=w1)
{
t=d1[p+q-i*2]; t%=Mod;
t*=comb(p+q-i*2,p-i); t%=Mod;
t*=d[i]; t%=Mod;
dap+=t;
dap%=Mod;
}
}
printf("%lld",dap);
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
32844 KB |
Output is correct |
2 |
Correct |
1 ms |
32844 KB |
Output is correct |
3 |
Correct |
0 ms |
32844 KB |
Output is correct |
4 |
Correct |
0 ms |
32844 KB |
Output is correct |
5 |
Correct |
0 ms |
32844 KB |
Output is correct |
6 |
Correct |
0 ms |
32844 KB |
Output is correct |
7 |
Correct |
1 ms |
32844 KB |
Output is correct |
8 |
Correct |
0 ms |
32844 KB |
Output is correct |
9 |
Correct |
0 ms |
32844 KB |
Output is correct |
10 |
Correct |
2 ms |
32844 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
32844 KB |
Output is correct |
2 |
Correct |
0 ms |
32844 KB |
Output is correct |
3 |
Correct |
0 ms |
32844 KB |
Output is correct |
4 |
Correct |
12 ms |
32844 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
32844 KB |
Output is correct |
2 |
Correct |
0 ms |
32844 KB |
Output is correct |
3 |
Correct |
0 ms |
32844 KB |
Output is correct |
4 |
Correct |
0 ms |
32844 KB |
Output is correct |
5 |
Correct |
0 ms |
32844 KB |
Output is correct |
6 |
Correct |
4 ms |
32844 KB |
Output is correct |
7 |
Correct |
6 ms |
32844 KB |
Output is correct |
8 |
Correct |
4 ms |
32844 KB |
Output is correct |
9 |
Correct |
0 ms |
32844 KB |
Output is correct |
10 |
Correct |
8 ms |
32844 KB |
Output is correct |