dgodfrey206’s gists

dgodfrey206 / largestproductinagrid.cpp

Created February 12, 2026 04:16

#11

	#include <bits/stdc++.h>
	#include <cassert>
	using namespace std;

	string s =
	"08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08\n\
	49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00\n\
	81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65\n\
	52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91\n\
	22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80\n\

dgodfrey206 / Summation of Primes.cpp

Created February 11, 2026 01:11

Find the sum of all the primes below two million.

	#include <bits/stdc++.h>
	#include <cassert>
	using namespace std;

	int main() {
	int n = 2e6;
	long long sum = 2;
	for (int i = 3; i < n; i += 2) {
	bool prime = true;
	for (int j = 2; j * j <= i; j++) {

dgodfrey206 / Special Pythagorean Triplet.cpp

Created February 11, 2026 00:43

There exists exactly one Pythagorean triplet for which a+b+c=100. Find the product abc.

	#include <bits/stdc++.h>
	using namespace std;

	// find two numbers who's squares, when added, equal a number whose square root, plus those two numbers equals 1000

	int main() {
	cout << []{
	int n = 1000;
	for (int a = 1; a <= n; a++) {
	for (int b = a + 1; b <= n; b++) {

dgodfrey206 / Largest Product in a Series.cpp

Created February 10, 2026 17:47

Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?

	#include <bits/stdc++.h>
	using namespace std;

	string num = "73167176531330624919225119674426574742355349194934\
	96983520312774506326239578318016984801869478851843\
	85861560789112949495459501737958331952853208805511\
	12540698747158523863050715693290963295227443043557\
	66896648950445244523161731856403098711121722383113\
	62229893423380308135336276614282806444486645238749\
	30358907296290491560440772390713810515859307960866\

dgodfrey206 / 10001st Prime.cpp

Created February 10, 2026 17:13

What is the 10001st prime number?

	#include <bits/stdc++.h>
	#include <cassert>
	using namespace std;

	int main() {
	int n = 10001;
	int limit = n/2;
	vector<int> prime;

	while (true) {

dgodfrey206 / sum_square_difference.cpp

Created February 10, 2026 15:49

Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

	#include <bits/stdc++.h>
	#include <cassert>
	using namespace std;

	int main() {
	int n = 100;
	int result = (n * (n + 1) * (3 * n * (n + 1) - 2 * (2 * n + 1)))/12;
	cout << result;
	}

dgodfrey206 / smallestmultiple.cpp

Created February 10, 2026 05:59

2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

	#include <bits/stdc++.h>
	#include <cassert>
	using namespace std;

	int main() {
	int n = 40;
	while (true) {
	bool found = true;
	for (int i = 2; i <= 20; i++) {
	if (n % i != 0) {

dgodfrey206 / largestprimefactor.cpp

Last active February 10, 2026 05:11

The prime factors of 13195 are 5,7,13 and 29. What is the largest prime factor of the number 600851475143?

	#include <bits/stdc++.h>
	#include <cassert>
	using namespace std;

	using ll = long long;

	int sieve() {
	ll n = 600851475143;
	ll sz = sqrt(n);
	vector<bool> prime(sz, true);

dgodfrey206 / kernel.cpp

Created February 8, 2026 01:48

	#include<vector>
	#include<functional>
	#include <bits/stdc++.h>
	using namespace std;

	enum ScalarType {
	UINT8,
	Float,
	Byte,
	};

dgodfrey206 / split.cpp

Created December 27, 2025 19:51

Split argument list

	#include <utility>
	#include <string>
	#include <tuple>
	#include <print>
	#include <functional>
	#include <concepts>
	#include <memory>
	#include <iostream>

	namespace detail {

David Godfrey dgodfrey206