CSES - HIIT Open 2019 - Results
Submission details
Task:Bit Strings
Sender:tykkipeli
Submission time:2019-05-25 13:08:39
Language:C++
Status:READY
Result:
Test results
testverdicttime
#1ACCEPTED0.02 sdetails
#2ACCEPTED0.02 sdetails
#3ACCEPTED0.02 sdetails
#4ACCEPTED0.02 sdetails
#5ACCEPTED0.02 sdetails
#6ACCEPTED0.03 sdetails
#7ACCEPTED0.03 sdetails
#8ACCEPTED0.01 sdetails
#9ACCEPTED0.02 sdetails
#10ACCEPTED0.02 sdetails
#110.05 sdetails
#12ACCEPTED0.07 sdetails
#130.07 sdetails
#140.07 sdetails
#15ACCEPTED0.07 sdetails
#160.07 sdetails
#170.07 sdetails
#18ACCEPTED0.05 sdetails

Code

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

ll M = 1e9 + 7;

ll pot[1010101];
ll dp[1010101];


int main() {
  ll n,k;
  cin >> n >> k;
  
  pot[0] = 1;
  for (int i = 1; i <= n; i++) {
      pot[i] = pot[i-1]*2;
      pot[i] = pot[i] % M;
  }
  
   for (int i = 0; i < k; i++) {
        dp[i] = pot[i];
   }
   dp[k] = pot[k]-1;
   for (int i = k+1; i <= n; i++) {
        dp[i] += dp[i-1];
        dp[i] += dp[i-1]- dp[i-k-1];
        dp[i] = dp[i] % M;
    }

    cout << dp[n] << endl;
}

Test details

Test 1

Verdict: ACCEPTED

input
1 1

correct output
1

user output
1

Test 2

Verdict: ACCEPTED

input
2 1

correct output
1

user output
1

Test 3

Verdict: ACCEPTED

input
2 2

correct output
3

user output
3

Test 4

Verdict: ACCEPTED

input
3 1

correct output
1

user output
1

Test 5

Verdict: ACCEPTED

input
3 2

correct output
5

user output
5

Test 6

Verdict: ACCEPTED

input
3 3

correct output
7

user output
7

Test 7

Verdict: ACCEPTED

input
4 1

correct output
1

user output
1

Test 8

Verdict: ACCEPTED

input
4 2

correct output
8

user output
8

Test 9

Verdict: ACCEPTED

input
4 3

correct output
13

user output
13

Test 10

Verdict: ACCEPTED

input
4 4

correct output
15

user output
15

Test 11

Verdict:

input
654321 123456

correct output
796245691

user output
-203754316

Test 12

Verdict: ACCEPTED

input
1000000 1

correct output
1

user output
1

Test 13

Verdict:

input
1000000 10

correct output
256933600

user output
-743066407

Test 14

Verdict:

input
1000000 100

correct output
142013415

user output
-857986592

Test 15

Verdict: ACCEPTED

input
1000000 1000

correct output
899626120

user output
899626120

Test 16

Verdict:

input
1000000 10000

correct output
374265948

user output
-625734059

Test 17

Verdict:

input
1000000 100000

correct output
388134512

user output
-611865495

Test 18

Verdict: ACCEPTED

input
1000000 1000000

correct output
235042058

user output
235042058