1. Visvesvaraya National Institute of Technology

2. COMPETITIVE
PROGRAMMING
WORKSHOP

3. Let’s Start With Maths...
To become a Pupil you need two things Maths and Maths
1.Prime Testing
2. Divisors and Prime Factors
3.GCD and LCM
4.Binary Expo
5.Modular Arithmetic
6.Permutations
CONTENTS

4. 3 Methods
Naive
Square root
Iterate on prime
1.
2.
3.
PRIME TESTING
1.

5. QUESTIONS

6. FACTORS
24 →1 2 3 4 6 8 12 24
**(the power of brute force)

7. GCD AND LCM
int gcd(int a,int b)
{
if(a%b==0)
return b;
else
return gcd(b,a%b);
}

8. Binary Expo
long long binpow(long long a, long long b) {
long long res = 1;
while (b > 0) {
if (b & 1)
res = res * a;
a = a * a;
b >>= 1;
}
return res;
}

9. Permutations

10. Modular Arithmetic
( a + b) % c = ( ( a % c ) + ( b % c ) ) % c
( a * b) % c = ( ( a % c ) * ( b % c ) ) % c
( a – b) % c = ( ( a % c ) – ( b % c ) ) % c
1.
2.
3.
Factorial wala example

11. Homework