#include <bits/stdc++.h>
#define dbgv(v) {for(auto x:v)cout<<x<<' ';cout<<'\n';}
#define entire(v) v.begin(),v.end()
typedef long long ll;
using namespace std;
void OJize(){
cin.tie(NULL); ios_base::sync_with_stdio(false);
#ifdef jh
freopen("input.txt", "r", stdin);
#endif
}
char s[7777];
char st[7777];
int top, idx;
const long long P=1000000007LL;
long long N,r,h,A,B,nofr,nofh;
long long ans,ansans;
long long llpow(long long x, long long n){
if(n==1) return x;
long long h=llpow(x,n/2);
if(n&1) return ((h*h)%P*x)%P;
return (h*h)%P;
}
long long invrh;
void push(char c){
st[++top]=c;
}
int main(){OJize();
cin>>N>>r>>h>>s>>A>>B;
invrh=llpow(r+h,P-2);
ans=1LL;
nofr=nofh=0;
for(int i=0;i<N;i++){
if(s[i]=='R') nofr++;
else nofh++;
}
for(int i=0;i<nofr-A;i++){
ans=((ans*r)%P*invrh)%P;
}
for(int i=0;i<nofh-B;i++){
ans=((ans*h)%P*invrh)%P;
}
if(N<=15){
if(nofr<A || nofh<B) cout<<0;
else{
ansans=0LL;
for(int i=0;i<(1<<(N-A-B));i++){
top=-1;
idx=0;
for(int j=0;j<N-A-B;j++){
while(idx <= N){
if(top > 0 && st[top]=='H' && st[top-1]=='R') break;
if(idx!=N) push(s[idx]);
idx++;
}
if(idx>N) break;
if(i&(1<<j)){
top--;
}
else{
top--;
st[top]='H';
}
}
for(;idx<N;idx++) push(s[idx]);
if(top==A+B-1){
int k;
for(k=0;k<B;k++){
if(st[k]!='H') break;
}
if(k==B){
for(k=0;k<A;k++){
if(st[B+k]!='R') break;
}
if(k==A) ansans++;
}
}
}
ans=(ans*ansans)%P;
cout<<ans;
}
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
248 KB |
Output is correct |
2 |
Correct |
2 ms |
360 KB |
Output is correct |
3 |
Correct |
2 ms |
392 KB |
Output is correct |
4 |
Correct |
2 ms |
648 KB |
Output is correct |
5 |
Correct |
3 ms |
648 KB |
Output is correct |
6 |
Correct |
3 ms |
668 KB |
Output is correct |
7 |
Correct |
4 ms |
668 KB |
Output is correct |
8 |
Correct |
3 ms |
668 KB |
Output is correct |
9 |
Correct |
2 ms |
668 KB |
Output is correct |
10 |
Correct |
2 ms |
668 KB |
Output is correct |
11 |
Correct |
2 ms |
668 KB |
Output is correct |
12 |
Correct |
2 ms |
668 KB |
Output is correct |
13 |
Correct |
3 ms |
668 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
3 ms |
668 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
248 KB |
Output is correct |
2 |
Correct |
2 ms |
360 KB |
Output is correct |
3 |
Correct |
2 ms |
392 KB |
Output is correct |
4 |
Correct |
2 ms |
648 KB |
Output is correct |
5 |
Correct |
3 ms |
648 KB |
Output is correct |
6 |
Correct |
3 ms |
668 KB |
Output is correct |
7 |
Correct |
4 ms |
668 KB |
Output is correct |
8 |
Correct |
3 ms |
668 KB |
Output is correct |
9 |
Correct |
2 ms |
668 KB |
Output is correct |
10 |
Correct |
2 ms |
668 KB |
Output is correct |
11 |
Correct |
2 ms |
668 KB |
Output is correct |
12 |
Correct |
2 ms |
668 KB |
Output is correct |
13 |
Correct |
3 ms |
668 KB |
Output is correct |
14 |
Incorrect |
3 ms |
668 KB |
Output isn't correct |
15 |
Halted |
0 ms |
0 KB |
- |