C++ code template for Competitive Coding

In this article, we have presented the complete C++ code template for Competitive Coding. It includes all basic functions for mathematical operations, bitwise operations, prime number generation, basic geometry, fast input and output and much more. Go through this template and use it in your contests.

Table of contents:

  1. Basic C++ Template
  2. C++ Template for basic Mathematics
  3. C++ Template for Efficient Bitwise Operations
  4. C++ Template for Prime Number Generation and tests
  5. C++ Template for basic Geometry
  6. Complete C++ template for Competitive Programming

Note: You can click copy at the top right corner of each code to copy the C++ Template code. You can paste it at your workspace/ code editor.

   MASTER COMPETITIVE PROGRAMMING WITH
       C++ TEMPLATE BY OPENGENUS
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              o8888888o 
              88" . "88 
              (| -_- |) 
              0\  =  /0 
            ___/`---'\___ 
          .' \\|     |// '. 
         / \\|||  :  |||// \ 
        / _||||| -:- |||||- \ 
       |   | \\\  -  /// |   | 
       | \_|  ''\---/''  |_/ | 
       \  .-\__  '-'  ___/-. / 
     ___'. .'  /--.--\  `. .'___ 
  ."" '<  `.___\_<|>_/___.' >' "". 
 | | :  `- \`.;`\ _ /`;.`/ - ` : | | 
 \  \ `_.   \_ __\ /__ _/   .-` /  / 
=====`-.____`.___ \_____/___.-`___.-'===== 
               `=---='

Basic C++ Template

Paste this C++ code template in your Coding Editor before solving any Competitive Programming question. Read the question and implement your solution over this. This C++ code template has basic marcos like ll for long long which will help you save typing time and a commented part to take input efficiently.

Go through this template once before your contest to know the features available. For useful values like MAXIMUM_NUMBER are defined as constants.

In the template, we have included two pragmas to optimize GCC compilation. During compilation, several options such as -O3 can be passed to improve performance but this is not in the control of the participants. So, the best we can do is to define GCC pargmas like:

#pragma GCC optimize("Ofast,unroll-loops") 
#pragma GCC target("avx,avx2,avx512,fma")

Note there are many header files in C++ but you only need bits/stdc++.h. This is advised as all required functions are available in it instead of including a bunch of different header files.

Fast input and output is very important and we acheive it by:

ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);

The complete basic C++ template is as follows:

#include <bits/stdc++.h>

using namespace std;

#pragma GCC optimize("Ofast,unroll-loops") 
#pragma GCC target("avx,avx2,avx512,fma") 

template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { os << '{'; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << '}'; }
void dbg_out() { cerr << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << ' ' << H; dbg_out(T...); }
#ifdef LOCAL
#define dbg(...) cerr << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

#define ar array
#define ll long long
#define ld long double
#define sza(x) ((int)x.size())
#define all(a) (a).begin(), (a).end()

#define PI 3.1415926535897932384626433832795l 
const int MAX_N = 1e5 + 5;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;
const ld EPS = 1e-9;

// -------------------------<RNG>------------------------- 
// RANDOM NUMBER GENERATOR
mt19937 RNG(chrono::steady_clock::now().time_since_epoch().count());  
#define SHUF(v) shuffle(all(v), RNG); 
// Use mt19937_64 for 64 bit random numbers.

void solve() {
    // Add your solution here
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t << ": ";
        solve();
    }
}

C++ Template for basic Mathematics

This template has basic functions for Mathematical operations that are frequently used in Competitive Coding such as Addition followed by Modulus (add), exponent, power, extended euclid, permutation, combination and much more.

Go through the available functions once before Contest so that you know which functions are available and use these instantly. Add this part to the above C++ code template. This is also included in the "Complete C++ template for Competitive Programming" section.

// ----------------------<MATH>--------------------------- 
 
template<typename T> T gcd(T a, T b){return(b?__gcd(a,b):a);} 

template<typename T> T lcm(T a, T b){return(a*(b/gcd(a,b)));} 

int add(int a, int b, int c = MOD){int res=a+b;
                         return(res>=c?res-c:res);} 
int mod_neg(int a, int b, int c = MOD){int res;
                         if(abs(a-b)<c)res=a-b;else res=(a-b)%c;
                         return(res<0?res+c:res);} 
int mul(int a, int b, int c = MOD){ll res=(ll)a*b;
                         return(res>=c?res%c:res);} 
int muln(int a, int b, int c = MOD){ll res=(ll)a*b;
                         return ((res%c)+c)%c;} 
ll mulmod(ll a,ll b, ll m = MOD){ll q = (ll)(((LD)a*(LD)b)/(LD)m);
                         ll r=a*b-q*m;if(r>m)r%=m;if(r<0)r+=m;return r;} 
template<typename T>T expo(T e, T n){T x=1,p=e;while(n)
                         {if(n&1)x=x*p;p=p*p;n>>=1;}return x;} 
template<typename T>T power(T e, T n, T m = MOD){T x=1,p=e;while(n)
                      {if(n&1)x=mul(x,p,m);p=mul(p,p,m);n>>=1;}return x;} 
template<typename T>T extended_euclid(T a, T b, T &x, T &y)
                    {T xx=0,yy=1;y=0;x=1;while(b){T q=a/b,t=b;b=a%b;a=t;\ 
t=xx;xx=x-q*xx;x=t;t=yy;yy=y-q*yy;y=t;}return a;}
template<typename T>T mod_inverse(T a, T n = MOD){T x,y,z=0;
               T d=extended_euclid(a,n,x,y);return(d>1?-1:mod_neg(x,z,n));} 
  
// Permutation and Combination
int ncr(int n,int r,int c = MOD){ 
    return mul(mul(ifact[r],ifact[n-r],c),fact[n],c); 
}  

// ----------------------</MATH>--------------------------

C++ Template for Efficient Bitwise Operations

Paste these Macros in the above code template if you need to use bitwise operations. This will help you do basic bitwise tasks instantly without having the need to think and implement it. For example, if you want to set the i-th bit of a number N to 1, then you can use the macro BIT_SET(N, 1). Similarly, you can use the other bitwise macros.

This has support for bit mask as well. In Competitive Programming, using bitwise operations in essential as you need to reduce the execution time to be within a given limit. For this, bitwise operation is an easy operation. Whereever possible, use bitwise operations.

// ----------------------</BITWISE>-------------------------- 
/* a=target variable, b=bit number to act upon 0-n */
#define BIT_SET(a,b) ((a) |= (1ULL<<(b)))
#define BIT_CLEAR(a,b) ((a) &= ~(1ULL<<(b)))
#define BIT_FLIP(a,b) ((a) ^= (1ULL<<(b)))

// '!!' to make sure this returns 0 or 1
#define BIT_CHECK(a,b) (!!((a) & (1ULL<<(b))))

#define BITMASK_SET(x, mask) ((x) |= (mask))
#define BITMASK_CLEAR(x, mask) ((x) &= (~(mask)))
#define BITMASK_FLIP(x, mask) ((x) ^= (mask))
#define BITMASK_CHECK_ALL(x, mask) (!(~(x) & (mask)))
#define BITMASK_CHECK_ANY(x, mask) ((x) & (mask))
// ----------------------</BITWISE END>--------------------------

C++ Template for Prime Number Generation and tests

3 main functions are provided in this template:

  • Sieve
  • Miller Rabin Test
  • Prime Factors
/****************** Prime Generator **********************/ 
const int N=1e7+10; int prime[20000010]; 
bool isprime[N]; int nprime; 
template <typename T> void Sieve(T a) 
{nprime = 0;memset(isprime,true,sizeof(isprime));
isprime[1]=false;for(int i=2;i<N;i++){
if(isprime[i]){prime[nprime++]=i;for(int j=2;i*j<N;j++)
isprime[i*j]=false;}}}

template <typename T> bool miller_rabin(T p, T itt) 
{if(p<2) return 0 ;if(p==2) return 1;if(p%2==0) 
return 0 ;ull s = p-1 ;while(s%2==0) s/=2;
for(ll i=1;i<=itt;i++) {ull a = rand() % (p-1)+1 , temp = s ;
ull mod = modulo(a,temp,(ull)p);while(mod!=1 and mod!=p-1 
and temp!=p-1){mod = Mulmod(mod,mod,(ull)p);temp*=2;}
if(temp%2==0 and mod!=p-1) return false ;}return true;} 

template <typename T> inline T PrimeFactors(T n)
{ll cnt=0,sum=1;for(int i=0; prime[i]*prime[i]<=n 
and i<nprime;i++){cnt=0;while(n%prime[i]==0)
{cnt++;n/=prime[i];}sum*=(cnt+1);}
if(n>1)sum*=2;return sum;} 
/****************** Prime Generator End **********************/

C++ Template for basic Geometry

This template include functions for basic geometry tasks such as:

  • Distance between two points
  • Distance between two points in 3D space
  • Volume of different shapes like rectangle, Pyramid and others

and many more.

Go through this template:

/****************** Geometry *****************/ 
template <typename T> inline T PointDistanceHorVer(T x1,T y1,T x2, T y2) 
{return abs(x1-x2)+abs(y1-y2);} 
template <typename T> inline T PointDistanceDiagonally(T x1,T y1,T x2, T y2) 
{return sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));} 
template <typename T> inline T PointDistanceMinimum(T x1,T y1,T x2, T y2) 
{ T tmp1=abs(x1-x2); T tmp2=abs(y1-y2); T tmp3=abs(tmp1-tmp2); 
T tmp4=min(tmp1, tmp2); return tmp3+tmp4; } 
template <typename T> inline T PointDistance3D(T x1,T y1,T z1,T x2,T y2,T z2)
{return sqrt(square(x2-x1)+square(y2-y1)+square(z2-z1));} 
 
template <typename T> inline T Cube(T a){return a*a*a;} 
template <typename T> inline T RectengularPrism(T a,T b,T c)
{return a*b*c;} 
template <typename T> inline T Pyramid(T base, T height)
{return (1/3)*base*height;} 
template <typename T> inline T Ellipsoid(T r1,T r2,T r3) 
{return (4/3)*PI*r1*r2*r3;} 
template <typename T> inline T IrregualarPrism(T base, T height)
{return base*height;} 
template <typename T> inline T Sphere(T radius)
{ return (4/3)*PI*radius*radius*radius;} 
template <typename T> inline T CylinderB(T base, T height)
{return base*height;} // base and height 
template <typename T> inline T CylinderR(T radius, T height)
{return PI*radius*radius*height;} // radius and height 
template <typename T> inline T Cone (T radius,T base, T height)
{return (1/3)*PI*radius*radius*height;} 
/****************** Geometry end *****************/

Complete C++ template for Competitive Programming

Following is the Complete C++ template for Competitive Programming including the templates for previous sections together. Use this:

#include <bits/stdc++.h>

using namespace std;

#pragma GCC optimize("Ofast,unroll-loops") 
#pragma GCC target("avx,avx2,avx512,fma") 

template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { os << '{'; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << '}'; }
void dbg_out() { cerr << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << ' ' << H; dbg_out(T...); }
#ifdef LOCAL
#define dbg(...) cerr << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

#define ar array
#define ll long long
#define ld long double
#define sza(x) ((int)x.size())
#define all(a) (a).begin(), (a).end()

#define PI 3.1415926535897932384626433832795l 
const int MAX_N = 1e5 + 5;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;
const ld EPS = 1e-9;

// -------------------------<RNG>------------------------- 
// RANDOM NUMBER GENERATOR
mt19937 RNG(chrono::steady_clock::now().time_since_epoch().count());  
#define SHUF(v) shuffle(all(v), RNG); 
// Use mt19937_64 for 64 bit random numbers.

// ----------------------</BITWISE>-------------------------- 
/* a=target variable, b=bit number to act upon 0-n */
#define BIT_SET(a,b) ((a) |= (1ULL<<(b)))
#define BIT_CLEAR(a,b) ((a) &= ~(1ULL<<(b)))
#define BIT_FLIP(a,b) ((a) ^= (1ULL<<(b)))

// '!!' to make sure this returns 0 or 1
#define BIT_CHECK(a,b) (!!((a) & (1ULL<<(b))))

#define BITMASK_SET(x, mask) ((x) |= (mask))
#define BITMASK_CLEAR(x, mask) ((x) &= (~(mask)))
#define BITMASK_FLIP(x, mask) ((x) ^= (mask))
#define BITMASK_CHECK_ALL(x, mask) (!(~(x) & (mask)))
#define BITMASK_CHECK_ANY(x, mask) ((x) & (mask))
// ----------------------</BITWISE END>-------------------------- 

// ----------------------<MATH>--------------------------- 
 
template<typename T> T gcd(T a, T b){return(b?__gcd(a,b):a);} 

template<typename T> T lcm(T a, T b){return(a*(b/gcd(a,b)));} 

int add(int a, int b, int c = MOD){int res=a+b;
                         return(res>=c?res-c:res);} 
int mod_neg(int a, int b, int c = MOD){int res;
                         if(abs(a-b)<c)res=a-b;else res=(a-b)%c;
                         return(res<0?res+c:res);} 
int mul(int a, int b, int c = MOD){ll res=(ll)a*b;
                         return(res>=c?res%c:res);} 
int muln(int a, int b, int c = MOD){ll res=(ll)a*b;
                         return ((res%c)+c)%c;} 
ll mulmod(ll a,ll b, ll m = MOD){ll q = (ll)(((LD)a*(LD)b)/(LD)m);
                         ll r=a*b-q*m;if(r>m)r%=m;if(r<0)r+=m;return r;} 
template<typename T>T expo(T e, T n){T x=1,p=e;while(n)
                         {if(n&1)x=x*p;p=p*p;n>>=1;}return x;} 
template<typename T>T power(T e, T n, T m = MOD){T x=1,p=e;while(n)
                      {if(n&1)x=mul(x,p,m);p=mul(p,p,m);n>>=1;}return x;} 
template<typename T>T extended_euclid(T a, T b, T &x, T &y)
                    {T xx=0,yy=1;y=0;x=1;while(b){T q=a/b,t=b;b=a%b;a=t;\ 
t=xx;xx=x-q*xx;x=t;t=yy;yy=y-q*yy;y=t;}return a;}
template<typename T>T mod_inverse(T a, T n = MOD){T x,y,z=0;
               T d=extended_euclid(a,n,x,y);return(d>1?-1:mod_neg(x,z,n));} 
  
// Permutation and Combination
int ncr(int n,int r,int c = MOD){ 
    return mul(mul(ifact[r],ifact[n-r],c),fact[n],c); 
}  

// ----------------------</MATH>-------------------------- 

/****************** Prime Generator **********************/ 
const int N=1e7+10; int prime[20000010]; 
bool isprime[N]; int nprime; 
template <typename T> void Sieve(T a) 
{nprime = 0;memset(isprime,true,sizeof(isprime));
isprime[1]=false;for(int i=2;i<N;i++){
if(isprime[i]){prime[nprime++]=i;for(int j=2;i*j<N;j++)
isprime[i*j]=false;}}}

template <typename T> bool miller_rabin(T p, T itt) 
{if(p<2) return 0 ;if(p==2) return 1;if(p%2==0) 
return 0 ;ull s = p-1 ;while(s%2==0) s/=2;
for(ll i=1;i<=itt;i++) {ull a = rand() % (p-1)+1 , temp = s ;
ull mod = modulo(a,temp,(ull)p);while(mod!=1 and mod!=p-1 
and temp!=p-1){mod = Mulmod(mod,mod,(ull)p);temp*=2;}
if(temp%2==0 and mod!=p-1) return false ;}return true;} 

template <typename T> inline T PrimeFactors(T n)
{ll cnt=0,sum=1;for(int i=0; prime[i]*prime[i]<=n 
and i<nprime;i++){cnt=0;while(n%prime[i]==0)
{cnt++;n/=prime[i];}sum*=(cnt+1);}
if(n>1)sum*=2;return sum;} 
/****************** Prime Generator End **********************/ 

/****************** Geometry *****************/ 
template <typename T> inline T PointDistanceHorVer(T x1,T y1,T x2, T y2) 
{return abs(x1-x2)+abs(y1-y2);} 
template <typename T> inline T PointDistanceDiagonally(T x1,T y1,T x2, T y2) 
{return sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1));} 
template <typename T> inline T PointDistanceMinimum(T x1,T y1,T x2, T y2) 
{ T tmp1=abs(x1-x2); T tmp2=abs(y1-y2); T tmp3=abs(tmp1-tmp2); 
T tmp4=min(tmp1, tmp2); return tmp3+tmp4; } 
template <typename T> inline T PointDistance3D(T x1,T y1,T z1,T x2,T y2,T z2)
{return sqrt(square(x2-x1)+square(y2-y1)+square(z2-z1));} 
 
template <typename T> inline T Cube(T a){return a*a*a;} 
template <typename T> inline T RectengularPrism(T a,T b,T c)
{return a*b*c;} 
template <typename T> inline T Pyramid(T base, T height)
{return (1/3)*base*height;} 
template <typename T> inline T Ellipsoid(T r1,T r2,T r3) 
{return (4/3)*PI*r1*r2*r3;} 
template <typename T> inline T IrregualarPrism(T base, T height)
{return base*height;} 
template <typename T> inline T Sphere(T radius)
{ return (4/3)*PI*radius*radius*radius;} 
template <typename T> inline T CylinderB(T base, T height)
{return base*height;} // base and height 
template <typename T> inline T CylinderR(T radius, T height)
{return PI*radius*radius*height;} // radius and height 
template <typename T> inline T Cone (T radius,T base, T height)
{return (1/3)*PI*radius*radius*height;} 
/****************** Geometry end *****************/ 

void solve() {
    // Add your solution here
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t << ": ";
        solve();
    }
}

With C++ template at OpenGenus, you must have full confidence to participate in your next Competitive Programming Contest. Go for it with the C++ template we provided.