Problem 47

47.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <stdbool.h>
+#include "primes.h"
+
+int numOfPrimeFactors (int n, long* primes) {
+    int rem = n;
+    int factors = 0;
+    for (int i = 0; primes[i] <= rem && primes[i] != n; i++) {
+        if (rem % primes[i] == 0) {
+            factors++;
+            while (rem != 0 && rem % primes[i] == 0) {
+                rem /= primes[i];
+            }
+            if (rem == 0)
+                break;
+        }
+    }
+    return factors;
+}
+
+int main () {
+    long n = 200000;
+    long* primes;
+    bool* primesTable;
+    listOfPrimes (n, &primes, &primesTable);
+
+    int consec = 0;
+    for (long i = 5; i <= n; i++) {
+        int factors = numOfPrimeFactors (i, primes);
+        consec = (factors == 4 ? consec + 1 : 0);
+        if (consec == 4) {
+            printf ("%d\n", i - 3);
+            break;
+        }
+    }
+}