#include <iostream>
#include <fstream>
#include <iomanip>
#include <vector>
#include <set>
#include <map>
#include <cstring>
#include <string>
#include <cmath>
#include <cassert>
#include <ctime>
#include <algorithm>
#include <sstream>
#include <list>
#include <queue>
#include <deque>
#include <stack>
#include <cstdlib>
#include <cstdio>
#include <iterator>
#include <functional>
#include <unordered_set>
#include <unordered_map>
#include <stdio.h>
#include <bitset>
#include <cstdint>
#include <cassert>
#include <functional>
#include <complex>
#include <random>
using namespace std;
#define ll long long
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ld long double
const ll maxn = 1e3 + 1, maxm = 1e3 + 1;
const ll mod = 1e9 + 7, cmod = 998244353, inf = 1e9, blcok = 400, p2 = 31;
const ld eps = 1e-9;
int n, k;
string s, l, r;
ll dp[maxn][maxn][2][2];
void add(ll &x, ll y){
x += y;
x %= mod;
}
ll get(string lim){
memset(dp, 0, sizeof(dp));
ll sum = 0;
lim = '#' + lim;
dp[1][0][0][1] = 1;
dp[1][0][1][1] = 1;
int m = (int)lim.size();
for (int i = 1; i < m - 1; ++i){
for (int j = 0; j <= k; ++j){
for (int fl = 0; fl < 2; ++fl){
for (int flg = 0; flg < 2; ++flg){
if (dp[i][j][fl][flg] > 0){
int ni = i + 1, nj = j, nfl = fl, nflg = flg;
if (s[i - 1] == 'L'){
if (fl == 0){
if (lim[i + 1] == '1'){
nflg = 0;
}
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
else{
if (lim[i + 1] == '1' || nflg == 0){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
}
else{
if (fl == 0){
if (lim[i + 1] == '1' || nflg == 0){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
else{
if (lim[i + 1] == '1'){
nflg = 0;
}
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
}
ni = i + 1, nj = j + 1, nfl = fl, nflg = flg;
if (j + 1 <= k){
nfl ^= 1;
int cfl = nfl;
if (s[i - 1] == 'L'){
if (cfl == 0){
if (lim[i + 1] == '1'){
nflg = 0;
}
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
else{
if (lim[i + 1] == '1' || nflg == 0){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
}
else{
if (cfl == 0){
if (lim[i + 1] == '1' || nflg == 0){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
else{
if (lim[i + 1] == '1'){
nflg = 0;
}
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
}
}
}
}
}
}
}
for (int i = 0; i < 2; ++i){
for (int j = 0; j < 2; ++j){
sum = (sum + dp[m - 1][k][i][j]) % mod;
}
}
return sum;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n >> k;
cin >> s;
cin >> l >> r;
ll ans = (get(r) - get(l) + mod) % mod;
memset(dp, 0, sizeof(dp));
string lim = l;
lim = '#' + lim;
dp[1][0][0][1] = 1;
dp[1][0][1][1] = 1;
int m = (int)lim.size();
for (int i = 1; i < m - 1; ++i){
for (int j = 0; j <= k; ++j){
for (int fl = 0; fl < 2; ++fl){
for (int flg = 0; flg < 2; ++flg){
if (dp[i][j][fl][flg] > 0){
int ni = i + 1, nj = j, nfl = fl, nflg = flg;
if (s[i - 1] == 'L'){
if (fl == 0){
if (lim[i + 1] == '0'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
}
else{
if (lim[i + 1] == '1'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
}
else{
if (fl == 0){
if (lim[i + 1] == '1'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
else{
if (lim[i + 1] == '0'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
}
}
if (j + 1 <= k){
nfl ^= 1;
nj = j + 1;
if (s[i - 1] == 'L'){
if (fl == 0){
if (lim[i + 1] == '0'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
}
else{
if (lim[i + 1] == '1'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
}
else{
if (fl == 0){
if (lim[i + 1] == '1'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2 + 1);
}
}
else{
if (lim[i + 1] == '0'){
add(dp[ni][nj][nfl][nflg], dp[i][j][fl][flg] * 2);
}
}
}
}
}
}
}
}
}
for (int i = 0; i < 2; ++i){
ans = (ans + dp[m - 1][k][i][1]) % mod;
}
cout << ans + (k > 0);
}
/*
*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
21 ms |
31632 KB |
Output is correct |
| 2 |
Correct |
19 ms |
31700 KB |
Output is correct |
| 3 |
Correct |
18 ms |
31600 KB |
Output is correct |
| 4 |
Correct |
17 ms |
31696 KB |
Output is correct |
| 5 |
Correct |
19 ms |
31572 KB |
Output is correct |
| 6 |
Correct |
19 ms |
31700 KB |
Output is correct |
| 7 |
Correct |
18 ms |
31652 KB |
Output is correct |
| 8 |
Correct |
18 ms |
31700 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
17 ms |
31572 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
37 ms |
31696 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
21 ms |
31632 KB |
Output is correct |
| 2 |
Correct |
19 ms |
31700 KB |
Output is correct |
| 3 |
Correct |
18 ms |
31600 KB |
Output is correct |
| 4 |
Correct |
17 ms |
31696 KB |
Output is correct |
| 5 |
Correct |
19 ms |
31572 KB |
Output is correct |
| 6 |
Correct |
19 ms |
31700 KB |
Output is correct |
| 7 |
Correct |
18 ms |
31652 KB |
Output is correct |
| 8 |
Correct |
18 ms |
31700 KB |
Output is correct |
| 9 |
Incorrect |
17 ms |
31572 KB |
Output isn't correct |
| 10 |
Halted |
0 ms |
0 KB |
- |
