2015/04

2015/04/src/main.rs

@@ -0,0 +1,48 @@
+extern crate crypto;
+
+
+use std::u64;
+
+use crypto::md5::Md5;
+use crypto::digest::Digest;
+
+
+fn main() {
+    println!("{:?}", process("ckczppom", "000000"));
+}
+
+fn process(secret: &str, starts_with: &str) -> Option<u64> {
+    let mut md5 = Md5::new();
+
+    for i in 1..u64::MAX {
+        let input = format!("{}{}", secret, i);
+
+        md5.input(input.as_bytes());
+
+        let result = md5.result_str();
+
+        if result.starts_with(starts_with) {
+            return Some(i);
+        }
+
+        md5.reset();
+    }
+
+    None
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::process;
+
+    #[test]
+    fn example_01() {
+        assert_eq!(Some(609043), process("abcdef", "00000"));
+    }
+
+    #[test]
+    fn example_02() {
+        assert_eq!(Some(1048970), process("pqrstuv", "00000"));
+    }
+}