Problem 53

53.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+long long choose (int n, int r) {
+    long long numerator = 1;
+    long long denominator = 1;
+    for (int i = 1; i <= r; i++) {
+        numerator *= n + 1 - i;
+        denominator *= i;
+    }
+    printf ("%d choose %d = %lli\n", n, r, numerator/denominator);
+    return numerator / denominator;
+}
+
+int main () {
+    int count = 4;
+    int n = 24;
+    int r = 10;
+
+    while (n <= 100) {
+        while (choose (n, r-1) > 1000000)
+            r--;
+        count += n - 2*r + 1;
+        n++;
+    }
+    printf ("Final r: %d; count: %d\n", r, count);
+}