Codeforces Round #412 (rated, Div. 1, based on VK Cup 2017 Round 3), problem: (F) Test Data Generation, Accepted Solution In C/C++

Affiliate Disclosure: This post contains Amazon affiliate links. If you purchase through these links, eBlogarithm may earn a commission at no extra cost to you. Prices and availability are subject to change.
#include<bits/stdc++.h>
#define ll long long

ll multmod(ll a, ll b, ll moder){
 a = (a % moder + moder) % moder, b = (b % moder + moder) % moder;
 ll ret = 0;
 for ( ; b; b >>= 1){
 if (b & 1){
 ret = ret + a >= moder ? ret + a - moder : ret + a;
 }
 a = a << 1 > moder ? (a << 1) - moder : a << 1;
 }
 return ret;
}

template <typename T> 
class modequa{
private:
 T remain, moder;
 
public:
 modequa <T>(){}
 modequa <T>(T remain, T moder) : remain(remain), moder(moder){}
 T getremain(){return remain;}
 T getmoder(){return moder;}
 
 void setvalue(T remain, T moder){
 this -> remain = remain;
 this -> moder = moder;
 }
 
 modequa <T> crt(const modequa <T> &p){
 T gcd = moder, x = 1, y = 0;
 for (T b = p.moder, x1 = 0, y1 = 1, r, s; b; ){
 r = x, s = y;
 x = x1, y = y1, x1 = r - x1 * (gcd / b), y1 = s - y1 * (gcd / b);
 r = gcd % b, gcd = b, b = r;
 }
 if ((p.remain - remain) % gcd) return modequa <T>(0, 0);
 T lcm = moder / gcd * p.moder;
 T ans = (p.remain - remain) / gcd;
 ans = multmod(multmod(ans, x, lcm), moder, lcm);
 ans += remain;
 ans += ans < 0 ? lcm : ans >= lcm ? -lcm : 0;
 return modequa <T>(ans, lcm);
 }
};

// Èç¹ûÄ£Êý²»ÊÇÖÊÊý£¬ÄÇô»ù±¾¾ÍÖ»ÄÜ×ö¼Ó¼õ³ËºÍÇóµ¼ÁËorz 
class poly{
private:
 int *a;
 int length, size;
 int moder, root, invroot;
 // ³£ÓõÄÁ½×éÄ£ÊýΪ ((119 << 23) + 1, 3, 332748118) ºÍ ((479 << 21) + 1, 3, 334845270)

 int powermod(int a, int exp, int moder)const &{
 int ret = 1;
 for ( ; exp; exp >>= 1){
 if (exp & 1){
 ret = 1ll * a * ret % moder;
 }
 a = 1ll * a * a % moder;
 }
 return ret;
 }
 
 void NTT(int *a, int length, int type, int moder, int root)const &{
 int len = -1;
 for (int x = length; x; ++ len, x >>= 1);
 for(int i = 1, j = 0; i < length - 1; ++ i){
 for(int s = length; j ^= s >>= 1, ~j & s; );
 if(i < j){
 std::swap(a[i], a[j]);
 }
 }
 for (int i = 1; i <= len; ++ i){
 int unit = powermod(root, moder - 1 >> i, moder);
 for (int j = 0; j < length; j += 1 << i){
 int w = 1;
 for (int k = j, szk = 1 << i - 1; k < j + szk; ++ k){
 int s = a[k], t = 1ll * w * a[k + szk] % moder;
 a[k] = s + t >= moder ? s + t - moder : s + t;
 a[k + szk] = s - t < 0 ? s - t + moder : s - t;
 w = 1ll * w * unit % moder;
 }
 }
 }
 if (type == 1) return;
 int inv = powermod(length, moder - 2, moder);
 for (int i = 0; i < length; ++ i){
 a[i] = 1ll * a[i] * inv % moder;
 }
 }
 
 void apply(int size){
 if (!size) return;
 a = new int [size]();
 this -> size = size;
 }
 
 void destroy(){
 if (!size) return;
 delete [] a;
 a = nullptr;
 }
 
 void resize(int size){
 if (!size) return;
 int *aux = a;
 a = new int [size]();
 memcpy(a, aux, sizeof(int) * (length + 1));
 if (this -> size) delete [] aux;
 this -> size = size;
 }

public:
 poly() : length(-1), moder(0), root(0), invroot(0){a = nullptr;}
 // Èç¹ûÄ£Êý·ÇNTTÖÊÊý root ºÍ invroot Ëæ±ãÉè¾ÍºÃÀ±~ 
 poly(int length, int moder, int root, int invroot):length(length), moder(moder), root(root), invroot(invroot){apply(length + 2 << 1);}
 poly(const poly &p):length(p.length), moder(p.moder), root(p.root), invroot(p.invroot){apply(p.size); memcpy(a, p.a, sizeof(int) * (p.length + 1));}
 poly(const poly &p, int length):length(length), moder(p.moder), root(p.root), invroot(p.invroot){apply(length + 2 << 1); memcpy(a, p.a, sizeof(int) * (std::min(length, p.length) + 1));}
 ~poly(){destroy();}
 void clear(){destroy(); length = -1, size = moder = root = invroot = 0;}
 int &operator [](int n){return a[n];}
 int getlength(){return length;}
 void setmoder(int moder, int root, int invroot){this -> moder = moder, this -> root = root, this -> invroot = invroot;}
 int getmoder(){return moder;}
 
 void setlength(int length){
 if (length >= size) resize(length + 2 << 1);
 if (length >= this -> length){
 this -> length = length;
 return;
 }
 memset(a + length + 1, 0, sizeof(int) * (this -> length - length));
 this -> length = length;
 }
 
 poly &operator = (const poly &p){
 destroy();
 apply(p.size);
 length = p.length;
 moder = p.moder;
 root = p.root;
 invroot = p.invroot;
 memcpy(a, p.a, sizeof(int) * (length + 1));
 return *this;
 }
 
 // Ï൱ÓÚ³ËÒÔ x ^ dis
 poly operator << (const int &dis)const &{
 poly ret(length + dis, moder, root, invroot);
 memcpy(ret.a + dis, a, sizeof(double) * (length + 1));
 return ret;
 }
 
 // Ï൱ÓÚ³ýÒÔ x ^ dis
 poly operator >> (const int &dis)const &{
 if (dis > length) return poly(-1, moder, root, invroot);
 poly ret(length - dis, moder, root, invroot);
 memcpy(ret.a, a + dis, sizeof(int) * (ret.length + 1));
 return ret;
 }
 
 int value(int x){
 int now = 1, ret = 0;
 for (int i = 0; i <= length; ++ i){
 ret = (ret + 1ll * a[i] * now) % moder;
 now = 1ll * now * x % moder;
 }
 return ret;
 }
 
 poly operator + (const poly &p)const &{
 if (!~length) return p;
 if (!~p.length) return *this;
 poly ret(*this, std::max(length, p.length));
 for (int i = 0; i <= p.length; ++ i){
 ret.a[i] += p.a[i];
 ret.a[i] -= ret.a[i] >= moder ? moder : 0;
 }
 for ( ; ~ret.length && !ret.a[ret.length]; -- ret.length)
 ;
 return ret;
 }
 
 poly operator - (const poly &p)const &{
 if (!~length) return p;
 if (!~p.length) return *this;
 poly ret(*this, std::max(length, p.length));
 for (int i = 0; i <= p.length; ++ i){
 ret.a[i] -= p.a[i];
 ret.a[i] += ret.a[i] < 0 ? moder : 0;
 }
 for ( ; ~ret.length && !ret.a[ret.length]; -- ret.length)
 ;
 return ret;
 }
 
 poly operator - ()const &{
 poly ret(length, moder, root, invroot);
 for (int i = 0; i <= length; ++ i){
 ret.a[i] = a[i] ? moder - a[i] : 0;
 }
 return ret;
 }
 /*&
 poly operator * (const poly &p)const &{
 if (!~length || !~p.length) return poly(-1, moder, root, invroot);
 int n = length + p.length;
 int lengthret = 1;
 for ( ; lengthret <= n; lengthret <<= 1)
 ;
 int *aux = new int [lengthret]();
 int *aux1 = new int [lengthret]();
 memcpy(aux, a, sizeof(int) * (length + 1));
 memcpy(aux1, p.a, sizeof(int) * (p.length + 1));
 NTT(aux, lengthret, 1, moder, root);
 NTT(aux1, lengthret, 1, moder, root);
 for (int i = 0; i < lengthret; ++ i){
 aux[i] = 1ll * aux[i] * aux1[i] % moder;
 }
 NTT(aux, lengthret, -1, moder, invroot);
 poly ret(n, moder, root, invroot);
 memcpy(ret.a, aux, sizeof(int) * (n + 1));
 delete [] aux;
 delete [] aux1;
 return ret;
 }*/
 
 ///*-------------------- ÕâÊÇÄ£Êý·ÇNTTÖÊÊýµÄÄ£°å£¬Çë°´ÐèÈ¡ÓÃ~ ------------------------------
 poly operator *(const poly &p)const &{
 const int multmoder[2] = {(119 << 23) + 1, (479 << 21) + 1};
 const int multroot[2] = {3, 3};
 const int multinvroot[2] = {332748118, 334845270};
 if (!~length || !~p.length) return poly(-1, moder, root, invroot);
 int n = length + p.length;
 int lengthret = 1;
 for ( ; lengthret <= n; lengthret <<= 1)
 ;
 int *aux = new int [lengthret]();
 int *aux1 = new int [lengthret]();
 int *aux2 = new int [lengthret]();
 memcpy(aux, a, sizeof(int) * (length + 1));
 memcpy(aux2, p.a, sizeof(int) * (p.length + 1));
 NTT(aux, lengthret, 1, multmoder[0], multroot[0]);
 NTT(aux2, lengthret, 1, multmoder[0], multroot[0]);
 for (int i = 0; i < lengthret; ++ i){
 aux[i] = 1ll * aux[i] * aux2[i] % multmoder[0];
 }
 NTT(aux, lengthret, -1, multmoder[0], multinvroot[0]);
 memcpy(aux1, a, sizeof(int) * (length + 1));
 memset(aux2, 0, sizeof(int) * lengthret);
 memcpy(aux2, p.a, sizeof(int) * (p.length + 1));
 NTT(aux1, lengthret, 1, multmoder[1], multroot[1]);
 NTT(aux2, lengthret, 1, multmoder[1], multroot[1]);
 for (int i = 0; i < lengthret; ++ i){
 aux1[i] = 1ll * aux1[i] * aux2[i] % multmoder[1];
 }
 NTT(aux1, lengthret, -1, multmoder[1], multinvroot[1]);
 poly ret(n, moder, root, invroot);
 for(int i = 0; i <= n; ++ i){
 modequa <ll> equa(aux[i], multmoder[0]), equb(aux1[i], multmoder[1]);
 ret.a[i] = equa.crt(equb).getremain() % moder;
 }
 delete [] aux;
 delete [] aux1;
 delete [] aux2;
 return ret;
 }
 //----------------------------------------------------------------------------------------*/
 
 poly operator * (const int &p)const &{
 int q = (p % moder + moder) % moder;
 if (!q) return poly(-1, moder, root, invroot);
 poly ret(length, moder, root, invroot);
 for (int i = 0; i <= length; ++ i){
 ret.a[i] = 1ll * a[i] * q % moder;
 }
 return ret;
 }
 
 friend poly operator * (const int &q, const poly &p){return p * q;}
 poly &operator += (const poly &p){*this = *this + p; return *this;}
 poly &operator -= (const poly &p){*this = *this - p; return *this;}
 poly &operator *= (const poly &p){*this = *this * p; return *this;}
 poly &operator *= (const int &p){*this = *this * p; return *this;}
};

const int N = 100;

int maxn, maxa, moder;
int q[N];

int main(){
 scanf("%d%d%d", &maxn, &maxa, &moder);
 if (maxa == 1){
 return printf("0\n"), 0;
 }
 int cnt = 0;
 for (maxa >>= 1; maxa; maxa >>= 1){
 q[cnt ++] = maxa;
 }
 std::reverse(q, q + cnt);
 int ans = 1;
 poly a(maxn, moder, 0, 0);
 poly b(maxn, moder, 0, 0);
 a[0] = 1;
 b[1] = 1;
 for (int i = 0; i < cnt - 1; ++ i){
 poly ret1(a);
 ret1 = (ret1 + b) * (q[i] & 1 ? b : a);
 if (q[i] & 1 ? b[0] : a[0]){
 ret1 -= b;
 }
 else{
 ret1 += a;
 }
 ret1.setlength(maxn);
 poly ret2(a);
 ret2 = (ret2 + b) * (q[i] & 1 ? a : b);
 if (q[i] & 1 ? a[0] : b[0]){
 ret2 -= a;
 }
 else{
 ret2 += b;
 }
 ret2.setlength(maxn);
 if (q[i + 1] & 1){
 a = ret1;
 for (int i = 1; i <= maxn; ++ i){
 b[i] = (ret2[i] + ret1[i - 1] + ret2[i - 1]) % moder;
 }
 }
 else{
 a = ret1;
 b = ret2;
 }
 for (int i = 1; i <= maxn; i += 2){
 ans = (ans + b[i]) % moder;
 }
 }
 return printf("%d\n", ans), 0;
}

Related Reading: Explore our comprehensive guide on Google Trends & technology research strategies.

📦 Looking for Codeforces Round 412 Div Based Vk? Check the best deals on Amazon.

🛒 Shop Codeforces Round 412 Div Based Vk on Amazon

As an Amazon Associate, eBlogarithm earns from qualifying purchases. Prices and availability are subject to change.

Affiliate Disclosure: This post contains Amazon affiliate links. If you purchase through these links, eBlogarithm may earn a commission at no extra cost to you. Prices and availability are subject to change.
#include<bits/stdc++.h>
#define ll long long

ll multmod(ll a, ll b, ll moder){
 a = (a % moder + moder) % moder, b = (b % moder + moder) % moder;
 ll ret = 0;
 for ( ; b; b >>= 1){
 if (b & 1){
 ret = ret + a >= moder ? ret + a - moder : ret + a;
 }
 a = a << 1 > moder ? (a << 1) - moder : a << 1;
 }
 return ret;
}

template <typename T> 
class modequa{
private:
 T remain, moder;
 
public:
 modequa <T>(){}
 modequa <T>(T remain, T moder) : remain(remain), moder(moder){}
 T getremain(){return remain;}
 T getmoder(){return moder;}
 
 void setvalue(T remain, T moder){
 this -> remain = remain;
 this -> moder = moder;
 }
 
 modequa <T> crt(const modequa <T> &p){
 T gcd = moder, x = 1, y = 0;
 for (T b = p.moder, x1 = 0, y1 = 1, r, s; b; ){
 r = x, s = y;
 x = x1, y = y1, x1 = r - x1 * (gcd / b), y1 = s - y1 * (gcd / b);
 r = gcd % b, gcd = b, b = r;
 }
 if ((p.remain - remain) % gcd) return modequa <T>(0, 0);
 T lcm = moder / gcd * p.moder;
 T ans = (p.remain - remain) / gcd;
 ans = multmod(multmod(ans, x, lcm), moder, lcm);
 ans += remain;
 ans += ans < 0 ? lcm : ans >= lcm ? -lcm : 0;
 return modequa <T>(ans, lcm);
 }
};

// Èç¹ûÄ£Êý²»ÊÇÖÊÊý£¬ÄÇô»ù±¾¾ÍÖ»ÄÜ×ö¼Ó¼õ³ËºÍÇóµ¼ÁËorz 
class poly{
private:
 int *a;
 int length, size;
 int moder, root, invroot;
 // ³£ÓõÄÁ½×éÄ£ÊýΪ ((119 << 23) + 1, 3, 332748118) ºÍ ((479 << 21) + 1, 3, 334845270)

 int powermod(int a, int exp, int moder)const &{
 int ret = 1;
 for ( ; exp; exp >>= 1){
 if (exp & 1){
 ret = 1ll * a * ret % moder;
 }
 a = 1ll * a * a % moder;
 }
 return ret;
 }
 
 void NTT(int *a, int length, int type, int moder, int root)const &{
 int len = -1;
 for (int x = length; x; ++ len, x >>= 1);
 for(int i = 1, j = 0; i < length - 1; ++ i){
 for(int s = length; j ^= s >>= 1, ~j & s; );
 if(i < j){
 std::swap(a[i], a[j]);
 }
 }
 for (int i = 1; i <= len; ++ i){
 int unit = powermod(root, moder - 1 >> i, moder);
 for (int j = 0; j < length; j += 1 << i){
 int w = 1;
 for (int k = j, szk = 1 << i - 1; k < j + szk; ++ k){
 int s = a[k], t = 1ll * w * a[k + szk] % moder;
 a[k] = s + t >= moder ? s + t - moder : s + t;
 a[k + szk] = s - t < 0 ? s - t + moder : s - t;
 w = 1ll * w * unit % moder;
 }
 }
 }
 if (type == 1) return;
 int inv = powermod(length, moder - 2, moder);
 for (int i = 0; i < length; ++ i){
 a[i] = 1ll * a[i] * inv % moder;
 }
 }
 
 void apply(int size){
 if (!size) return;
 a = new int [size]();
 this -> size = size;
 }
 
 void destroy(){
 if (!size) return;
 delete [] a;
 a = nullptr;
 }
 
 void resize(int size){
 if (!size) return;
 int *aux = a;
 a = new int [size]();
 memcpy(a, aux, sizeof(int) * (length + 1));
 if (this -> size) delete [] aux;
 this -> size = size;
 }

public:
 poly() : length(-1), moder(0), root(0), invroot(0){a = nullptr;}
 // Èç¹ûÄ£Êý·ÇNTTÖÊÊý root ºÍ invroot Ëæ±ãÉè¾ÍºÃÀ±~ 
 poly(int length, int moder, int root, int invroot):length(length), moder(moder), root(root), invroot(invroot){apply(length + 2 << 1);}
 poly(const poly &p):length(p.length), moder(p.moder), root(p.root), invroot(p.invroot){apply(p.size); memcpy(a, p.a, sizeof(int) * (p.length + 1));}
 poly(const poly &p, int length):length(length), moder(p.moder), root(p.root), invroot(p.invroot){apply(length + 2 << 1); memcpy(a, p.a, sizeof(int) * (std::min(length, p.length) + 1));}
 ~poly(){destroy();}
 void clear(){destroy(); length = -1, size = moder = root = invroot = 0;}
 int &operator [](int n){return a[n];}
 int getlength(){return length;}
 void setmoder(int moder, int root, int invroot){this -> moder = moder, this -> root = root, this -> invroot = invroot;}
 int getmoder(){return moder;}
 
 void setlength(int length){
 if (length >= size) resize(length + 2 << 1);
 if (length >= this -> length){
 this -> length = length;
 return;
 }
 memset(a + length + 1, 0, sizeof(int) * (this -> length - length));
 this -> length = length;
 }
 
 poly &operator = (const poly &p){
 destroy();
 apply(p.size);
 length = p.length;
 moder = p.moder;
 root = p.root;
 invroot = p.invroot;
 memcpy(a, p.a, sizeof(int) * (length + 1));
 return *this;
 }
 
 // Ï൱ÓÚ³ËÒÔ x ^ dis
 poly operator << (const int &dis)const &{
 poly ret(length + dis, moder, root, invroot);
 memcpy(ret.a + dis, a, sizeof(double) * (length + 1));
 return ret;
 }
 
 // Ï൱ÓÚ³ýÒÔ x ^ dis
 poly operator >> (const int &dis)const &{
 if (dis > length) return poly(-1, moder, root, invroot);
 poly ret(length - dis, moder, root, invroot);
 memcpy(ret.a, a + dis, sizeof(int) * (ret.length + 1));
 return ret;
 }
 
 int value(int x){
 int now = 1, ret = 0;
 for (int i = 0; i <= length; ++ i){
 ret = (ret + 1ll * a[i] * now) % moder;
 now = 1ll * now * x % moder;
 }
 return ret;
 }
 
 poly operator + (const poly &p)const &{
 if (!~length) return p;
 if (!~p.length) return *this;
 poly ret(*this, std::max(length, p.length));
 for (int i = 0; i <= p.length; ++ i){
 ret.a[i] += p.a[i];
 ret.a[i] -= ret.a[i] >= moder ? moder : 0;
 }
 for ( ; ~ret.length && !ret.a[ret.length]; -- ret.length)
 ;
 return ret;
 }
 
 poly operator - (const poly &p)const &{
 if (!~length) return p;
 if (!~p.length) return *this;
 poly ret(*this, std::max(length, p.length));
 for (int i = 0; i <= p.length; ++ i){
 ret.a[i] -= p.a[i];
 ret.a[i] += ret.a[i] < 0 ? moder : 0;
 }
 for ( ; ~ret.length && !ret.a[ret.length]; -- ret.length)
 ;
 return ret;
 }
 
 poly operator - ()const &{
 poly ret(length, moder, root, invroot);
 for (int i = 0; i <= length; ++ i){
 ret.a[i] = a[i] ? moder - a[i] : 0;
 }
 return ret;
 }
 /*&
 poly operator * (const poly &p)const &{
 if (!~length || !~p.length) return poly(-1, moder, root, invroot);
 int n = length + p.length;
 int lengthret = 1;
 for ( ; lengthret <= n; lengthret <<= 1)
 ;
 int *aux = new int [lengthret]();
 int *aux1 = new int [lengthret]();
 memcpy(aux, a, sizeof(int) * (length + 1));
 memcpy(aux1, p.a, sizeof(int) * (p.length + 1));
 NTT(aux, lengthret, 1, moder, root);
 NTT(aux1, lengthret, 1, moder, root);
 for (int i = 0; i < lengthret; ++ i){
 aux[i] = 1ll * aux[i] * aux1[i] % moder;
 }
 NTT(aux, lengthret, -1, moder, invroot);
 poly ret(n, moder, root, invroot);
 memcpy(ret.a, aux, sizeof(int) * (n + 1));
 delete [] aux;
 delete [] aux1;
 return ret;
 }*/
 
 ///*-------------------- ÕâÊÇÄ£Êý·ÇNTTÖÊÊýµÄÄ£°å£¬Çë°´ÐèÈ¡ÓÃ~ ------------------------------
 poly operator *(const poly &p)const &{
 const int multmoder[2] = {(119 << 23) + 1, (479 << 21) + 1};
 const int multroot[2] = {3, 3};
 const int multinvroot[2] = {332748118, 334845270};
 if (!~length || !~p.length) return poly(-1, moder, root, invroot);
 int n = length + p.length;
 int lengthret = 1;
 for ( ; lengthret <= n; lengthret <<= 1)
 ;
 int *aux = new int [lengthret]();
 int *aux1 = new int [lengthret]();
 int *aux2 = new int [lengthret]();
 memcpy(aux, a, sizeof(int) * (length + 1));
 memcpy(aux2, p.a, sizeof(int) * (p.length + 1));
 NTT(aux, lengthret, 1, multmoder[0], multroot[0]);
 NTT(aux2, lengthret, 1, multmoder[0], multroot[0]);
 for (int i = 0; i < lengthret; ++ i){
 aux[i] = 1ll * aux[i] * aux2[i] % multmoder[0];
 }
 NTT(aux, lengthret, -1, multmoder[0], multinvroot[0]);
 memcpy(aux1, a, sizeof(int) * (length + 1));
 memset(aux2, 0, sizeof(int) * lengthret);
 memcpy(aux2, p.a, sizeof(int) * (p.length + 1));
 NTT(aux1, lengthret, 1, multmoder[1], multroot[1]);
 NTT(aux2, lengthret, 1, multmoder[1], multroot[1]);
 for (int i = 0; i < lengthret; ++ i){
 aux1[i] = 1ll * aux1[i] * aux2[i] % multmoder[1];
 }
 NTT(aux1, lengthret, -1, multmoder[1], multinvroot[1]);
 poly ret(n, moder, root, invroot);
 for(int i = 0; i <= n; ++ i){
 modequa <ll> equa(aux[i], multmoder[0]), equb(aux1[i], multmoder[1]);
 ret.a[i] = equa.crt(equb).getremain() % moder;
 }
 delete [] aux;
 delete [] aux1;
 delete [] aux2;
 return ret;
 }
 //----------------------------------------------------------------------------------------*/
 
 poly operator * (const int &p)const &{
 int q = (p % moder + moder) % moder;
 if (!q) return poly(-1, moder, root, invroot);
 poly ret(length, moder, root, invroot);
 for (int i = 0; i <= length; ++ i){
 ret.a[i] = 1ll * a[i] * q % moder;
 }
 return ret;
 }
 
 friend poly operator * (const int &q, const poly &p){return p * q;}
 poly &operator += (const poly &p){*this = *this + p; return *this;}
 poly &operator -= (const poly &p){*this = *this - p; return *this;}
 poly &operator *= (const poly &p){*this = *this * p; return *this;}
 poly &operator *= (const int &p){*this = *this * p; return *this;}
};

const int N = 100;

int maxn, maxa, moder;
int q[N];

int main(){
 scanf("%d%d%d", &maxn, &maxa, &moder);
 if (maxa == 1){
 return printf("0\n"), 0;
 }
 int cnt = 0;
 for (maxa >>= 1; maxa; maxa >>= 1){
 q[cnt ++] = maxa;
 }
 std::reverse(q, q + cnt);
 int ans = 1;
 poly a(maxn, moder, 0, 0);
 poly b(maxn, moder, 0, 0);
 a[0] = 1;
 b[1] = 1;
 for (int i = 0; i < cnt - 1; ++ i){
 poly ret1(a);
 ret1 = (ret1 + b) * (q[i] & 1 ? b : a);
 if (q[i] & 1 ? b[0] : a[0]){
 ret1 -= b;
 }
 else{
 ret1 += a;
 }
 ret1.setlength(maxn);
 poly ret2(a);
 ret2 = (ret2 + b) * (q[i] & 1 ? a : b);
 if (q[i] & 1 ? a[0] : b[0]){
 ret2 -= a;
 }
 else{
 ret2 += b;
 }
 ret2.setlength(maxn);
 if (q[i + 1] & 1){
 a = ret1;
 for (int i = 1; i <= maxn; ++ i){
 b[i] = (ret2[i] + ret1[i - 1] + ret2[i - 1]) % moder;
 }
 }
 else{
 a = ret1;
 b = ret2;
 }
 for (int i = 1; i <= maxn; i += 2){
 ans = (ans + b[i]) % moder;
 }
 }
 return printf("%d\n", ans), 0;
}

Related Reading: Explore our comprehensive guide on Google Trends & technology research strategies.

📦 Looking for Codeforces Round 412 Div Based Vk? Check the best deals on Amazon.

🛒 Shop Codeforces Round 412 Div Based Vk on Amazon

As an Amazon Associate, eBlogarithm earns from qualifying purchases. Prices and availability are subject to change.

More from author

LEAVE A REPLY

Please enter your comment!
Please enter your name here

Related posts

Advertismentspot_img

Latest posts

Is Viral Kitchen Gadgets Worth Your Money Here Is Our Full Review

📢 As an Amazon Associate, I earn from qualifying purchases.If you had told me six months ago that a single purchase would change how...

Where Is the Outrage? Profound Autism Didn’t Used to Exist — Now It’s Everywhere

Decades ago, the landscape of primary education looked radically different than it does today. In the late 1970s, typical elementary school environments rarely featured...

How Viral Kitchen Gadgets Is Quietly Changing the Game

📢 As an Amazon Associate, I earn from qualifying purchases.Most products in this category disappoint within weeks. Cheap materials, vague instructions, and results that...

Want to stay up to date with the latest news?

We would love to hear from you! Please fill in your details and we will stay in touch. It's that simple!