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  1. #include <iostream>
  2. #include <algorithm>
  3. #define llong long long
  4.  
  5. using namespace std;
  6.  
  7. int n, k;
  8. llong dp[10006], tmp[10006];
  9. const int mod = 1e9+7;
  10.  
  11. int main() {
  12.     cin >> n >> k;
  13.     for(int i=1; i<=n; ++i) {
  14.         tmp[0] = 1;
  15.         for(int j=1; j<=k; ++j) {
  16.             llong val = (dp[j] - ((j - i >= 0) ? dp[j-i] : 0) + mod) % mod;
  17.             tmp[j] = (tmp[j-1] + val) % mod;
  18.         }
  19.         for(int j=0; j<=k; ++j) dp[j] = tmp[j];
  20.     }
  21.     cout << (dp[k] - ((k > 0) ? dp[k-1] : 0) + mod) % mod;
  22.     return 0;
  23. }
Success #stdin #stdout 0s 4516KB
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Standard input is empty
stdout 
Standard output is empty
https://ideone.com/ZvkbfM
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

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