#include <bits/stdc++.h>
using namespace std;
#define inf 1000000000000000007
using ll = long long;
int n, m;
ll mod, wynik, dp[2][10000007], pom;
int main ()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> mod;
for (int i=1; i<=m; i++)
dp[0][i] = m-i+1;
for (int poz=2; poz<=n; poz++)
{
dp[1][1] = 0;
for (int i=1; i<=m; i++)
{
dp[1][1] += (ll)(m-i+1)*dp[0][i];
dp[1][1] %= mod;
}
pom = dp[0][1];
for (int i=2; i<=m; i++)
{
ll odejmij = (ll)(m-i+1)*dp[0][m-i+2];
odejmij %= mod;
dp[1][i] = dp[1][i-1] + mod + mod - pom - odejmij;
dp[1][i] %= mod;
pom += dp[0][i] + mod - dp[0][m-i+2];
pom %= mod;
}
for (int i=1; i<=m; i++)
{
dp[0][i] = dp[1][i];
dp[1][i] = 0;
}
}
for (int i=1; i<=m; i++)
{
wynik += dp[0][i];
wynik %= mod;
}
cout << wynik << "\n";
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | #include <bits/stdc++.h> using namespace std; #define inf 1000000000000000007 using ll = long long; int n, m; ll mod, wynik, dp[2][10000007], pom; int main () { ios_base::sync_with_stdio(0); cin.tie(0); cin >> n >> m >> mod; for (int i=1; i<=m; i++) dp[0][i] = m-i+1; for (int poz=2; poz<=n; poz++) { dp[1][1] = 0; for (int i=1; i<=m; i++) { dp[1][1] += (ll)(m-i+1)*dp[0][i]; dp[1][1] %= mod; } pom = dp[0][1]; for (int i=2; i<=m; i++) { ll odejmij = (ll)(m-i+1)*dp[0][m-i+2]; odejmij %= mod; dp[1][i] = dp[1][i-1] + mod + mod - pom - odejmij; dp[1][i] %= mod; pom += dp[0][i] + mod - dp[0][m-i+2]; pom %= mod; } for (int i=1; i<=m; i++) { dp[0][i] = dp[1][i]; dp[1][i] = 0; } } for (int i=1; i<=m; i++) { wynik += dp[0][i]; wynik %= mod; } cout << wynik << "\n"; return 0; } |
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