2 files changed, 31 insertions, 1 deletions
diff --git a/src/2015/day4/aoc.cpp b/src/2015/day4/aoc.cpp
index 6e47928..1bb0d4e 100644
--- a/src/2015/day4/aoc.cpp
+++ b/src/2015/day4/aoc.cpp
@@ -1,3 +1,30 @@
 #include "aoc.h"
 
-namespace aoc2015 {}
+namespace aoc2015 {
+
+char* md5sum(char* s) {
+  static char md5[64] = {0};
+  uint8_t* x = md5String(s);
+  memset(md5, 0x0, 64);
+  for (auto i = 0; i < 16; i++) {
+    sprintf(md5 + i * 2, "%02x", x[i]);
+  }
+  return md5;
+}
+
+int lead_zeros(char* s) {
+  char* p = s;
+  int total = 0;
+  while (*p != '\0') {
+    if (*p == '0') {
+      total += 1;
+      p++;
+    }
+    else {
+      break;
+    }
+  }
+  return total;
+}
+
+} // namespace aoc2015
diff --git a/src/2015/day4/aoc.h b/src/2015/day4/aoc.h
index c8a6225..56d8ba3 100644
--- a/src/2015/day4/aoc.h
+++ b/src/2015/day4/aoc.h
@@ -4,4 +4,7 @@
 
 namespace aoc2015 {
 
+char* md5sum(char *);
+int lead_zeros(char*);
+
 }