oj.uz

Submission #1011084

# Submission time Handle Problem Language Result Execution time Memory
1011084 2024-06-29T18:54:03 Z ksu2009en Ljetopica (COI19_ljetopica) C++14
100 / 100
 35 ms 32092 KB 
#include <iostream>
#include <vector>
#include <string>
#include <math.h>
#include <cmath>
#include <iomanip>
#include <cstdio>
#include <algorithm>
#include <numeric>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <deque>
#include <bitset>
#include <cstring>
#include <unordered_map>
 
using namespace std;
typedef long long ll;
 
ll dp[1007][1007][2], pw[10007];
ll sum[1007][1007][2];
ll const mod = (ll)(1e9 + 7);
 
ll get(string &a, string b, ll n, ll k, bool inclusive){
    for(int i = 0; i <= n + 1; i++)
        for(int j = 0; j <= k + 1; j++)
            dp[i][j][0] = dp[i][j][1] = 0;
    
    dp[n][0][1] = 1;
    dp[n][1][0] = 1;
    dp[n][0][0] = 1;
    dp[n][1][1] = 1;
    
    if(a[n] == '0'){
        sum[n][0][1] = 1;
        sum[n][1][0] = 1;
    }
    else{
        sum[n][0][0] = 1;
        sum[n][1][1] = 1;
    }
    
    for(int i = n - 1; i >= 1; i--){
        for(int j = 0; j <= k + 1; j++){
            // no add inverse:
                // inverse before:
            char c = (a[i] == '0' ? '1' : '0');
            sum[i][j][1] = (((c == '0' ? 0 : pw[n - i]) * dp[i + 1][j][1]) % mod + sum[i + 1][j][1]) % mod;
            dp[i][j][1] = dp[i + 1][j][1];
            
                // no inverse before
            
            sum[i][j][0] = (((a[i] == '0' ? 0 : pw[n - i]) * dp[i + 1][j][0]) % mod + sum[i + 1][j][0]) % mod;
            dp[i][j][0] = dp[i + 1][j][0];
            
            // add inverse:
            if(j != 0){
                // inverse before = 0 inverse
                sum[i][j][1] = (sum[i][j][1] + (((a[i] == '0' ? 0 : pw[n - i]) * dp[i + 1][j - 1][0]) % mod + sum[i + 1][j - 1][0]) % mod) % mod;
                dp[i][j][1] = (dp[i][j][1] + dp[i + 1][j - 1][0]) % mod;
                
                // no inverse before
                char c = (a[i] == '0' ? '1' : '0');
                sum[i][j][0] = (sum[i][j][0] + (((c == '0' ? 0 : pw[n - i]) * dp[i + 1][j - 1][1]) % mod + sum[i + 1][j - 1][1]) % mod) % mod;
                dp[i][j][0] = (dp[i][j][0] + dp[i + 1][j - 1][1]) % mod;
            }
        }
    }
//    for(int i = 1; i <= n; i++){
//        for(int j = 0; j <= k; j++){
//            cout << i << ' ' << j << ":  " << dp[i][j][0] << ' ' << dp[i][j][1] << endl;
//        }
//        cout << endl << endl;
//    }
//
//    cout << "_____________" << endl;
//
//    for(int i = 1; i <= n; i++){
//        for(int j = 0; j <= k; j++){
//            cout << i << ' ' << j << ":  " << sum[i][j][0] << ' ' << sum[i][j][1] << endl;
//        }
//        cout << endl << endl;
//    }
    
    ll ans = 0, need = 0, last = 0;
    ll cur = pw[n];
    
    for(int i = 1; i <= n; i++){
        // i = first position < b[i]
        
        if(b[i] == '0'){
            if(a[i] != b[i]){
                if(last == 0){
                    need++;
                }
                last = 1;
            }
            else{
                if(last == 1)
                    need++;
                
                last = 0;
            }
            
            continue;
        }
        
        ll need2 = need;
        ll last2 = last;
        
        if(a[i] == '0'){
            if(last == 1){
                need2++;
            }
            last2 = 0;
        }
        else{
            if(last == 0){
                need2++;
            }
            last2 = 1;
        }
        
        ll left0 = k - need2;
        //cout << "     " << i << ' ' << left0 << ' ' << last2 << endl;
        
        bool firstinversion = false;
        if(i == 1){
            if(a[1] == '1')
                firstinversion = true;
        }
        else{
            if(a[1] != b[1])
                firstinversion = true;
        }
        
        ll possible = left0 - (firstinversion ? -1 : 1);
        
        ll cnt = 0;
        if(i == n){
            if(left0 == 0 || possible == 0){
                cnt = cur;
            }
        }
        else{
            if(left0 >= 0){
                cnt = (cur * dp[i + 1][left0][last2]) % mod;
                cnt = (cnt + sum[i + 1][left0][last2]) % mod;
            }
            
            //cout << "!!  " << i << ' ' << left0 << ' ' << dp[i + 1][left0][last2] << ' ' << sum[i + 1][left0][last2] << ' ' << cnt << endl;
            
            if(possible >= 0){
                ll cnt2 = ((cur * dp[i + 1][possible][last2]) % mod) % mod;
                cnt2 = (cnt2 + sum[i + 1][possible][last2]) % mod;
                
                cnt = (cnt + cnt2) % mod;
                
                //cout << "??  " << i << ' ' << possible << ' ' << dp[i + 1][possible][last2] << ' ' << sum[i + 1][possible][last2] << ' ' << cnt2 << endl;
            }
        }
        
        ans = (ans + cnt) % mod;
        //cout << cnt << endl;
        
        //cout << "last " << last << endl;
        if(a[i] != b[i]){
            if(last == 0){
                need++;
            }
            last = 1;
        }
        else{
            if(last == 1){
                need++;
            }
            last = 0;
 
        }
        
        cur = (cur + (b[i] == '0' ? 0 : pw[n - i])) % mod;
    }
//    cout << need << ' ' << cur << ' '<< (k - need)<< endl;
    
    if(inclusive){
        if(k - need == 0){
            ans = (ans + cur) % mod;
        }
        else{
            bool firstinversion = false;
            if(a[1] != b[1])
                firstinversion = true;
            
            ll possible = k - need - (firstinversion ? -1 : 1);
            
            if(possible == 0)
                ans = (ans + cur) % mod;
        }
    }
    
    return ans;
}
 
int main(){
    pw[0] = 1;
    
    for(int i = 1; i <= 1001; i++)
        pw[i] = (pw[i - 1] * 2) % mod;
    
    ll n, k;
    cin >> n >> k;
    n--;
    
    string a;
    cin >> a;
    
    for(auto &i: a)
        i = (i == 'L' ? '0' : '1');
    a = '#' + a;
    
    string b, c;
    cin >> b >> c;
    
    auto h2 = get(a, c, n, k, true);


//    cout << h2 << endl;
//
//    return 0;
////
    auto h1 = get(a, b, n, k, false);

    ll ans = (h2 - h1) % mod;
    if(ans < 0)
        ans += mod;
    
    cout << ans << endl;
     
    return 0;
}
/*
 4 2
 LRR
 1000
 1111
 
 */

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 31320 KB Output is correct
2 Correct 3 ms 31068 KB Output is correct
3 Correct 3 ms 31068 KB Output is correct
4 Correct 3 ms 31068 KB Output is correct
5 Correct 3 ms 29020 KB Output is correct
6 Correct 2 ms 26968 KB Output is correct
7 Correct 2 ms 26972 KB Output is correct
8 Correct 2 ms 22876 KB Output is correct

Subtask #2
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4440 KB Output is correct
2 Correct 1 ms 4444 KB Output is correct
3 Correct 1 ms 4528 KB Output is correct
4 Correct 1 ms 4444 KB Output is correct
5 Correct 1 ms 4444 KB Output is correct
6 Correct 1 ms 4440 KB Output is correct
7 Correct 1 ms 4444 KB Output is correct
8 Correct 1 ms 4444 KB Output is correct
9 Correct 1 ms 4544 KB Output is correct
10 Correct 1 ms 4440 KB Output is correct
11 Correct 1 ms 4444 KB Output is correct
12 Correct 1 ms 4444 KB Output is correct
13 Correct 1 ms 4444 KB Output is correct
14 Correct 1 ms 4444 KB Output is correct
15 Correct 1 ms 4444 KB Output is correct

Subtask #3
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 31836 KB Output is correct
2 Correct 16 ms 31576 KB Output is correct
3 Correct 18 ms 31836 KB Output is correct
4 Correct 34 ms 32092 KB Output is correct
5 Correct 16 ms 31580 KB Output is correct
6 Correct 35 ms 32092 KB Output is correct
7 Correct 11 ms 31928 KB Output is correct
8 Correct 18 ms 31836 KB Output is correct
9 Correct 3 ms 31428 KB Output is correct
10 Correct 17 ms 31732 KB Output is correct

Subtask #4
61.0 / 61.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 31320 KB Output is correct
2 Correct 3 ms 31068 KB Output is correct
3 Correct 3 ms 31068 KB Output is correct
4 Correct 3 ms 31068 KB Output is correct
5 Correct 3 ms 29020 KB Output is correct
6 Correct 2 ms 26968 KB Output is correct
7 Correct 2 ms 26972 KB Output is correct
8 Correct 2 ms 22876 KB Output is correct
9 Correct 1 ms 4440 KB Output is correct
10 Correct 1 ms 4444 KB Output is correct
11 Correct 1 ms 4528 KB Output is correct
12 Correct 1 ms 4444 KB Output is correct
13 Correct 1 ms 4444 KB Output is correct
14 Correct 1 ms 4440 KB Output is correct
15 Correct 1 ms 4444 KB Output is correct
16 Correct 1 ms 4444 KB Output is correct
17 Correct 1 ms 4544 KB Output is correct
18 Correct 1 ms 4440 KB Output is correct
19 Correct 1 ms 4444 KB Output is correct
20 Correct 1 ms 4444 KB Output is correct
21 Correct 1 ms 4444 KB Output is correct
22 Correct 1 ms 4444 KB Output is correct
23 Correct 1 ms 4444 KB Output is correct
24 Correct 21 ms 31836 KB Output is correct
25 Correct 16 ms 31576 KB Output is correct
26 Correct 18 ms 31836 KB Output is correct
27 Correct 34 ms 32092 KB Output is correct
28 Correct 16 ms 31580 KB Output is correct
29 Correct 35 ms 32092 KB Output is correct
30 Correct 11 ms 31928 KB Output is correct
31 Correct 18 ms 31836 KB Output is correct
32 Correct 3 ms 31428 KB Output is correct
33 Correct 17 ms 31732 KB Output is correct
34 Correct 30 ms 31832 KB Output is correct
35 Correct 13 ms 31208 KB Output is correct
36 Correct 17 ms 31320 KB Output is correct
37 Correct 32 ms 31392 KB Output is correct
38 Correct 7 ms 31068 KB Output is correct
39 Correct 28 ms 31324 KB Output is correct
40 Correct 6 ms 31064 KB Output is correct
41 Correct 19 ms 31580 KB Output is correct
42 Correct 28 ms 31836 KB Output is correct
43 Correct 25 ms 31408 KB Output is correct
44 Correct 28 ms 31324 KB Output is correct
45 Correct 10 ms 31064 KB Output is correct
46 Correct 25 ms 31320 KB Output is correct
47 Correct 27 ms 31576 KB Output is correct
48 Correct 16 ms 31336 KB Output is correct
49 Correct 4 ms 31068 KB Output is correct
50 Correct 29 ms 31740 KB Output is correct
51 Correct 14 ms 31324 KB Output is correct
52 Correct 15 ms 31324 KB Output is correct
53 Correct 34 ms 32000 KB Output is correct
54 Correct 12 ms 31580 KB Output is correct
55 Correct 27 ms 32088 KB Output is correct
56 Correct 31 ms 32092 KB Output is correct
57 Correct 6 ms 31320 KB Output is correct
58 Correct 24 ms 31832 KB Output is correct