initial commit

1 files changed, 31 insertions, 0 deletions

diff --git a/euler19.c b/euler19.c
new file mode 100644
index 0000000..78a9d55
--- /dev/null
+++ b/euler19.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+
+const int days[2][12]={
+	{31,28,31,30,31,30,31,31,30,31,30,31},
+	{31,29,31,30,31,30,31,31,30,31,30,31}};
+
+int isleap(int y)
+{
+	if (y%4==0 && (y%100!=0 || y%400==0))
+		return 1;
+	else
+		return 0;
+}
+
+int main()
+{
+	int y,m,t;
+	int d=1+365,count=0;
+	for (y=1901;y<=2000;++y){
+		t=isleap(y);
+		for (m=0;m<12;++m){
+			d%=7;
+			if (d==0)
+				++count;
+			d+=days[t][m];
+		}
+	}
+	printf("%d\n",count);
+	return 0;
+}
+