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Submission #1108455

# Submission time Handle Problem Language Result Execution time Memory
1108455 2024-11-04T07:38:31 Z juliany2 Ljetopica (COI19_ljetopica) C++17
100 / 100
 87 ms 64080 KB 
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) (x).begin(), (x).end()

const int mod = 1e9 + 7;

const int N = 1007;
int n, m;
string s, l, r;
ll p2[N];
// [idx][flips][last][restricted]
ll cnt[N][N][2][2], sum[N][N][2][2];

ll solve(string x) {
    memset(cnt, 0, sizeof(cnt));
    memset(sum, 0, sizeof(sum));

    cnt[0][0][0][1] = cnt[0][0][1][1] = 1;

    for (int i = 1; i < n; i++) {
        for (int j = 0; j <= m; j++) {
            for (int k : {0, 1}) {
                int p = s[i] == '1';
                int q = p ^ 1;

                if (x[i] == '0') {
                    (cnt[i][j + (k != q)][q][1] += cnt[i - 1][j][k][1]) %= mod;
                    (sum[i][j + (k != q)][q][1] += sum[i - 1][j][k][1]) %= mod;
                }
                else {
                    (cnt[i][j + (k != p)][p][1] += cnt[i - 1][j][k][1]) %= mod;
                    (sum[i][j + (k != p)][p][1] += sum[i - 1][j][k][1]) %= mod;
                    (sum[i][j + (k != p)][p][1] += cnt[i - 1][j][k][1] * p2[i] % mod) %= mod;

                    (cnt[i][j + (k != q)][q][0] += cnt[i - 1][j][k][1]) %= mod;
                    (sum[i][j + (k != q)][q][0] += sum[i - 1][j][k][1]) %= mod;
                }

                (cnt[i][j + (k != p)][p][0] += cnt[i - 1][j][k][0]) %= mod;
                (sum[i][j + (k != p)][p][0] += sum[i - 1][j][k][0]) %= mod;
                (sum[i][j + (k != p)][p][0] += cnt[i - 1][j][k][0] * p2[i] % mod) %= mod;

                (cnt[i][j + (k != q)][q][0] += cnt[i - 1][j][k][0]) %= mod;
                (sum[i][j + (k != q)][q][0] += sum[i - 1][j][k][0]) %= mod;
            }
        }
    }

    ll res = 0;
    for (int j : {0, 1}) {
        for (int k : {0, 1}) {
            (res += sum[n - 1][m][j][k]) %= mod;
            (res += cnt[n - 1][m][j][k] * p2[0] % mod) %= mod;
        }
    }

    return res;
}

int main() {
    cin.tie(0)->sync_with_stdio(false);

    cin >> n >> m >> s >> l >> r;

    for (char &c : s) {
        c = (c == 'L' ? '0' : '1');
    }
    s = '1' + s;

    p2[n - 1] = 1;
    for (int i = n - 2; i >= 0; i--)
        p2[i] = p2[i + 1] * 2 % mod;

    ll ans = (solve(r) - solve(l) + mod) % mod;

    int cnt = 0;
    int lst = l[1] == s[1];
    for (int i = 2; i < n; i++) {
        int here = l[i] == s[i];
        if (here != lst)
            cnt++;
        lst = here;
    }

    if (cnt == m - 1 || cnt == m) {
        for (int i = 0; i < n; i++) {
            if (l[i] == '1')
                (ans += p2[i]) %= mod;
        }
    }

    cout << ans << '\n';

    return 0;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 63824 KB Output is correct
2 Correct 13 ms 63824 KB Output is correct
3 Correct 13 ms 63980 KB Output is correct
4 Correct 14 ms 63824 KB Output is correct
5 Correct 13 ms 63980 KB Output is correct
6 Correct 13 ms 63824 KB Output is correct
7 Correct 13 ms 63824 KB Output is correct
8 Correct 14 ms 63800 KB Output is correct

Subtask #2
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 63824 KB Output is correct
2 Correct 13 ms 63824 KB Output is correct
3 Correct 13 ms 63824 KB Output is correct
4 Correct 12 ms 63964 KB Output is correct
5 Correct 13 ms 63908 KB Output is correct
6 Correct 12 ms 63996 KB Output is correct
7 Correct 12 ms 63824 KB Output is correct
8 Correct 13 ms 63956 KB Output is correct
9 Correct 12 ms 63836 KB Output is correct
10 Correct 14 ms 63824 KB Output is correct
11 Correct 13 ms 63824 KB Output is correct
12 Correct 12 ms 63824 KB Output is correct
13 Correct 15 ms 63808 KB Output is correct
14 Correct 12 ms 63824 KB Output is correct
15 Correct 13 ms 63824 KB Output is correct

Subtask #3
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 63824 KB Output is correct
2 Correct 46 ms 63824 KB Output is correct
3 Correct 48 ms 63824 KB Output is correct
4 Correct 84 ms 63836 KB Output is correct
5 Correct 38 ms 63824 KB Output is correct
6 Correct 87 ms 63824 KB Output is correct
7 Correct 30 ms 63824 KB Output is correct
8 Correct 45 ms 63992 KB Output is correct
9 Correct 13 ms 63824 KB Output is correct
10 Correct 42 ms 63824 KB Output is correct

Subtask #4
61.0 / 61.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 63824 KB Output is correct
2 Correct 13 ms 63824 KB Output is correct
3 Correct 13 ms 63980 KB Output is correct
4 Correct 14 ms 63824 KB Output is correct
5 Correct 13 ms 63980 KB Output is correct
6 Correct 13 ms 63824 KB Output is correct
7 Correct 13 ms 63824 KB Output is correct
8 Correct 14 ms 63800 KB Output is correct
9 Correct 14 ms 63824 KB Output is correct
10 Correct 13 ms 63824 KB Output is correct
11 Correct 13 ms 63824 KB Output is correct
12 Correct 12 ms 63964 KB Output is correct
13 Correct 13 ms 63908 KB Output is correct
14 Correct 12 ms 63996 KB Output is correct
15 Correct 12 ms 63824 KB Output is correct
16 Correct 13 ms 63956 KB Output is correct
17 Correct 12 ms 63836 KB Output is correct
18 Correct 14 ms 63824 KB Output is correct
19 Correct 13 ms 63824 KB Output is correct
20 Correct 12 ms 63824 KB Output is correct
21 Correct 15 ms 63808 KB Output is correct
22 Correct 12 ms 63824 KB Output is correct
23 Correct 13 ms 63824 KB Output is correct
24 Correct 57 ms 63824 KB Output is correct
25 Correct 46 ms 63824 KB Output is correct
26 Correct 48 ms 63824 KB Output is correct
27 Correct 84 ms 63836 KB Output is correct
28 Correct 38 ms 63824 KB Output is correct
29 Correct 87 ms 63824 KB Output is correct
30 Correct 30 ms 63824 KB Output is correct
31 Correct 45 ms 63992 KB Output is correct
32 Correct 13 ms 63824 KB Output is correct
33 Correct 42 ms 63824 KB Output is correct
34 Correct 63 ms 63824 KB Output is correct
35 Correct 33 ms 63996 KB Output is correct
36 Correct 43 ms 63976 KB Output is correct
37 Correct 80 ms 63824 KB Output is correct
38 Correct 21 ms 63824 KB Output is correct
39 Correct 72 ms 63968 KB Output is correct
40 Correct 22 ms 63824 KB Output is correct
41 Correct 51 ms 63824 KB Output is correct
42 Correct 63 ms 63824 KB Output is correct
43 Correct 63 ms 63824 KB Output is correct
44 Correct 71 ms 63824 KB Output is correct
45 Correct 29 ms 64080 KB Output is correct
46 Correct 59 ms 63824 KB Output is correct
47 Correct 67 ms 63992 KB Output is correct
48 Correct 39 ms 63992 KB Output is correct
49 Correct 15 ms 63824 KB Output is correct
50 Correct 75 ms 63824 KB Output is correct
51 Correct 39 ms 63824 KB Output is correct
52 Correct 40 ms 63824 KB Output is correct
53 Correct 84 ms 63972 KB Output is correct
54 Correct 32 ms 63824 KB Output is correct
55 Correct 67 ms 63824 KB Output is correct
56 Correct 78 ms 63824 KB Output is correct
57 Correct 19 ms 63824 KB Output is correct
58 Correct 62 ms 63824 KB Output is correct