Fixed solution for ex 8 with an old solution to a similar exercise

1 files changed, 11 insertions, 1 deletions

diff --git a/Year 1/Programming introduction/Practice-02.10.21.cpp b/Year 1/Programming introduction/Practice-02.10.21.cpp
index 0c524f3..960e211 100644
--- a/Year 1/Programming introduction/Practice-02.10.21.cpp
+++ b/Year 1/Programming introduction/Practice-02.10.21.cpp
@@ -148,7 +148,17 @@ void ex7() {
 // (f(a, b) == f(c, d)) ⇐⇒ (a == c & b == d)
 
 int f(int a, int b) {
-	return fac(a) + fac(b);
+	// This is some old code of mine: https://gitlab.com/Syndamia/algorithms/-/blob/master/C_C++/FindSpiralNumber.cpp
+	int n, v = max(abs(a), abs(b)), g = 8 * (v * (v + 1) / 2);
+
+	if (b == v || a == v) { // Top row or right column
+		n = g - a + b - 6 * v;
+	}
+	else { // Left column or bottom row
+		n = g + a - b - 2 * v;
+	}
+
+	return n;
 }
 
 void ex8() {