Add 20104.cpp

Author: Hiyabye

20xxx/20104.cpp

@@ -0,0 +1,16 @@
+#include "timecard.h"
+
+static int N;
+
+void init(int n) {
+  N = n;
+}
+
+std::string convert(std::string s) {
+  for (char &c : s) {
+    if ('A' <= c && c <= 'Z') {
+      c = c - 'A' + 'a';
+    }
+  }
+  return s;
+}