Submission #706954

#	Time	Username	Problem	Language	Result	Execution time	Memory
706954		Nursik	Ljetopica (COI19_ljetopica)	C++14	8 / 100	42 ms	31700 KiB

ljetopica

#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;
                            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);
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    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;

}
/*
*/

• Subtask 1: 8 / 8
• Subtask 2: 0 / 14
• Subtask 3: 0 / 17
• Subtask 4: 0 / 61