[w10] Added solutions

5 files changed, 119 insertions, 0 deletions

diff --git a/week10/ex1.cpp b/week10/ex1.cpp
new file mode 100644
index 0000000..9467043
--- /dev/null
+++ b/week10/ex1.cpp
@@ -0,0 +1,13 @@
+#include <iostream>
+
+int gcd(int a, int b) {
+	if (a == b) return a;
+	if (a > b)  return gcd(a-b, b);
+	return gcd(b, a);
+}
+
+int main() {
+	int a, b;
+	std::cin >> a >> b;
+	std::cout << gcd(a, b) << std::endl;
+}
diff --git a/week10/ex2.cpp b/week10/ex2.cpp
new file mode 100644
index 0000000..3d3e9a1
--- /dev/null
+++ b/week10/ex2.cpp
@@ -0,0 +1,12 @@
+#include <iostream>
+
+int fibIndex(const int N, int count = 0, int a = 0, int b = 1) {
+	if (N == a) return count;
+	return fibIndex(N, count + 1, b, a+b);
+}
+
+int main() {
+	int N;
+	std::cin >> N;
+	std::cout << fibIndex(N) << std::endl;
+}
diff --git a/week10/ex3.cpp b/week10/ex3.cpp
new file mode 100644
index 0000000..1edf55d
--- /dev/null
+++ b/week10/ex3.cpp
@@ -0,0 +1,27 @@
+#include <iostream>
+
+void printCharNTimes(int n, char c) {
+	for (int i = 0; i < n; i++) {
+		std::cout << c;
+	}
+}
+
+void hourglass(int lines, int whitespaces, int nonwhitespace) {
+	if (lines == 0) return;
+
+	printCharNTimes(whitespaces, ' ');
+	printCharNTimes(nonwhitespace, '+');
+	std::cout << std::endl;
+
+	hourglass(lines - 1, whitespaces + 1, nonwhitespace - 2);
+
+	printCharNTimes(whitespaces, ' ');
+	printCharNTimes(nonwhitespace, '#');
+	std::cout << std::endl;
+}
+
+int main() {
+	int N;
+	std::cin >> N;
+	hourglass(N, 0, 2*N - 1);
+}
diff --git a/week10/ex4.cpp b/week10/ex4.cpp
new file mode 100644
index 0000000..ec05144
--- /dev/null
+++ b/week10/ex4.cpp
@@ -0,0 +1,23 @@
+#include <iostream>
+
+void printNumbers(int currentBit, char* buf, const int N) {
+	if (currentBit == 0) {
+		std::cout << buf << std::endl;
+		return;
+	}
+	buf[N - currentBit] = '0';
+	printNumbers(currentBit - 1, buf, N);
+	buf[N - currentBit] = '1';
+	printNumbers(currentBit - 1, buf, N);
+}
+
+int main() {
+	int N;
+	std::cin >> N;
+
+	char* buf = new char[N+1];
+	buf[N] = '\0';
+
+	printNumbers(N, buf, N);
+	delete[] buf;
+}
diff --git a/week10/ex5.cpp b/week10/ex5.cpp
new file mode 100644
index 0000000..895c729
--- /dev/null
+++ b/week10/ex5.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+#include <cstring>
+
+void skipWhitespaces(char*& str) {
+	while (*str == ' ') str++;
+}
+
+int calculateExpression(char*& expr) {
+	if (*expr == '\0') return 0;
+
+	skipWhitespaces(expr);
+
+	// Ако започваме с цифра, връщаме числото и го пропускаме в израза
+	if ('0' <= expr[0] && expr[0] <= '9') {
+		int ret = atoi(expr);
+		while ('0' <= *expr && *expr <= '9') expr++;
+		return ret;
+	}
+
+	expr++; // пропускаме (
+	int leftHandSide = calculateExpression(expr);
+	skipWhitespaces(expr);
+
+	char op = *expr;
+	expr++;
+
+	skipWhitespaces(expr);
+	int rightHandSide = calculateExpression(expr);
+
+	skipWhitespaces(expr);
+	expr++; // пропускаме )
+	
+	if (op == '+') {
+		return leftHandSide + rightHandSide;
+	}
+	return leftHandSide * rightHandSide;
+}
+
+int main() {
+	char buf[1025];
+	std::cin.getline(buf, 1025);
+	char* ptrCopy = buf;
+	std::cout << calculateExpression(ptrCopy) << std::endl;
+}