Diff
Not logged in

Differences From Artifact [76c58f82b36b80e2]:

To Artifact [4dd19b13cd92c7f0]:


1 1 2 2 //------------------------------------------------------------- 3 3 // Modulo Arithmetics 4 4 // 5 5 // Verified by 6 6 // - TCO10 R3 LV3 7 +// - SRM 545 LV2 7 8 //------------------------------------------------------------- 8 9 9 -static const int MODVAL = 1000000007; // must be prime for op/ 10 +static const int MODVAL = 1000000007; 10 11 struct mint 11 12 { 12 13 int val; 13 14 mint():val(0){} 14 - mint(int x):val(x%MODVAL) {} // x>=0 15 - mint(size_t x):val(x%MODVAL) {} // x>=0 16 - mint(LL x):val(x%MODVAL) {} // x>=0 15 + mint(int x):val(x%MODVAL) {} 16 + mint(size_t x):val(x%MODVAL) {} 17 + mint(LL x):val(x%MODVAL) {} 17 18 }; 18 19 mint& operator+=(mint& x, mint y) { return x = x.val+y.val; } 19 20 mint& operator-=(mint& x, mint y) { return x = x.val-y.val+MODVAL; } 20 21 mint& operator*=(mint& x, mint y) { return x = LL(x.val)*y.val; } 21 22 mint POW(mint x, LL e) { mint v=1; for(;e;x*=x,e>>=1) if(e&1) v*=x; return v; } 22 23 mint& operator/=(mint& x, mint y) { return x *= POW(y, MODVAL-2); } 23 24 mint operator+(mint x, mint y) { return x+=y; } ................................................................................ 24 25 mint operator-(mint x, mint y) { return x-=y; } 25 26 mint operator*(mint x, mint y) { return x*=y; } 26 27 mint operator/(mint x, mint y) { return x/=y; } 27 28 vector<mint> FAC_(1,1); 28 29 mint FAC(LL n) { while( FAC_.size()<=n ) FAC_.push_back( FAC_.back()*FAC_.size() ); return FAC_[n]; } 29 30 mint C(LL n, LL k) { return k<0 || n<k ? 0 : FAC(n) / (FAC(k) * FAC(n-k)); } 30 31 32 +// Pascal's triangle: if O(1) nCk is needed. 33 +vector< vector<mint> > CP_(2001); 34 +mint C(LL n, LL k) { 35 + if(CP_[0].empty()) { 36 + CP_[0].push_back(1); 37 + for(int nn=1; nn<CP_.size(); ++nn) 38 + for(int kk=0; kk<=nn; ++kk) 39 + CP_[nn].push_back( (kk?CP_[nn-1][kk-1]:0) + (kk<nn?CP_[nn-1][kk]:0) ); 40 + } 41 + return k<0 || n<k ? 0 : CP_[n][k]; 42 +} 31 43 32 44 33 45 34 46 /* 35 47 // MODVAL must be a prime!! 36 48 LL GSS(LL k, LL b, LL e) // k^b + k^b+1 + ... + k^e 37 49 {