Update euler-0027.cpp

euler-0027.cpp

@@ -33,63 +33,50 @@
 
 #include <iostream>
 
-// return true if x is prime
+// Function to check if a number is prime
 bool isPrime(int x)
 {
-  // reject invalid input
-  if (x <= 1)
-    return false;
-
-  // process all potential divisors
-  for (int factor = 2; factor*factor <= x; factor++)
-    if (x % factor == 0)
-      return false;
-
-  // no such divisor found, it's a prime number
-  return true;
+    if (x <= 1) return false;
+    for (int factor = 2; factor * factor <= x; factor++)
+        if (x % factor == 0) return false;
+    return true;
 }
 
 int main()
 {
-  // upper and lower limit of the coefficients
-  int limit;
-  std::cin >> limit;
-  // make sure it's a positive number
-  if (limit < 0)
-    limit = -limit;
+    int limit;
+    std::cin >> limit;
+
+    // Ensure limit is positive
+    if (limit < 0) limit = -limit;
+
+    int bestA = 0, bestB = 0;
+    int maxConsecutivePrimes = 0;
 
-  // keep track of best sequence:
-  // number of generated primes
-  unsigned int consecutive = 0;
-  // its coefficients
-  int bestA = 0;
-  int bestB = 0;
+    // Iterate over coefficients a and b
+    for (int a = -limit; a <= limit; a++) {
+        for (int b = 2; b <= limit; b++) { // Only check positive primes for b
+            if (!isPrime(b)) continue; // Skip non-prime values of b
 
-  // simple brute-force approach
-  for (int a = -limit; a <= +limit; a++)
-    for (int b = -limit; b <= +limit; b++)
-    {
-      // count number of consecutive prime numbers
-      unsigned int length = 0;
-      while (isPrime(length * length + a * length + b))
-        length++;
+            int length = 0;
 
-      // better than before ?
-      if (consecutive < length)
-      {
-        consecutive = length;
-        bestA = a;
-        bestB = b;
-      }
+            // Count consecutive primes
+            while (isPrime(length * length + a * length + b)) {
+                length++;
+            }
+
+            // Update best coefficients if a longer sequence is found
+            if (length > maxConsecutivePrimes) {
+                maxConsecutivePrimes = length;
+                bestA = a;
+                bestB = b;
+            }
+        }
     }
 
-#define ORIGINAL
-#ifdef ORIGINAL
-  // print a*b
-  std::cout << (bestA * bestB) << std::endl;
-#else
-  // print best factors
-  std::cout << bestA << " " << bestB << std::endl;
-#endif
-  return 0;
+    // Print best coefficients
+    std::cout << bestA << " " << bestB << std::endl;
+
+    return 0;
 }
+