[w4] Added old solution to ex 2HEADmain

1 files changed, 83 insertions, 0 deletions

diff --git a/week04/exercise02.cpp b/week04/exercise02.cpp
new file mode 100644
index 0000000..4b08d53
--- /dev/null
+++ b/week04/exercise02.cpp
@@ -0,0 +1,83 @@
+#include <iostream>
+
+unsigned long long tenTo(unsigned long long power) {
+	unsigned long long result = 1;
+	while (power > 0) {
+		result *= 10;
+		power--;
+	}
+	return result;
+}
+
+unsigned numLen(unsigned long long n) {
+	if (n == 0) return 1;
+	unsigned len = 0;
+	while (n > 0) {
+		len++;
+		n /= 10;
+	}
+	return len;
+}
+
+unsigned long long insert(unsigned long long n, unsigned start, unsigned len, unsigned long long toInsert) {
+	unsigned numDigits = numLen(n);
+	return (n / tenTo(numDigits - start + 1)) * tenTo(numDigits - start + len + 1)
+	       + toInsert * tenTo(numDigits - start + 1)
+	       + n % tenTo(numDigits - start + 1);
+}
+
+unsigned long long append(unsigned long long n, unsigned long long appendWith) {
+	return insert(n, numLen(n) + 1, numLen(appendWith), appendWith);
+}
+
+unsigned long long reverse(unsigned long long n) {
+	unsigned long long rev = 0;
+	while (n > 0) {
+		rev *= 10;
+		rev += n % 10;
+		n /= 10;
+	}
+	return rev;
+}
+
+unsigned bitLength(unsigned long long num) {
+	unsigned length = 0;
+	while (num > 0) {
+		length++;
+		num >>= 1;
+	}
+	return length - 1;
+}
+
+unsigned max(unsigned a, unsigned b) {
+	return (a > b) ? a : b;
+}
+
+unsigned nthDigit(unsigned long long n, unsigned digit) {
+	while (digit > 0) {
+		n /= 10;
+		digit--;
+	}
+	return n % 10;
+}
+
+int main() {
+	// TODO: make more readable
+	unsigned long long p1, c1, p2, c2;
+	std::cin >> p1 >> c1 >> p2 >> c2;
+	unsigned long long pm = 0, cm = 0;
+	unsigned maxPower = bitLength(p1) + bitLength(p2);
+	for (unsigned power = 0; power <= maxPower; power++) {
+		int coeff = 0;
+		for (int pow1 = 0; pow1 <= power; pow1++) {
+			for (int pow2 = 0; pow2 <= power; pow2++) {
+				if ((pow1 + pow2 != power) || (((p1 >> pow1) & 1) == 0) || (((p2 >> pow2) & 1) == 0)) continue;
+				coeff += nthDigit(c1, pow1) * nthDigit(c2, pow2);
+			}
+		}
+		pm <<= 1;
+		pm |= coeff > 0;
+		cm = append(cm, coeff);
+	}
+	std::cout << pm << std::endl << reverse(cm) << std::endl;
+}