1 files changed, 54 insertions, 0 deletions
diff --git a/03/src/part-1.rs b/03/src/part-1.rs
new file mode 100644
index 0000000..f682ef3
--- /dev/null
+++ b/03/src/part-1.rs
@@ -0,0 +1,54 @@
+use std::io::{BufRead};
+
+fn main() {    
+    let stdin = std::io::stdin();
+    let mut handle = stdin.lock();
+    
+    let mut buf: Vec<u8> = Vec::new();
+
+    let mut result: usize = 0;
+    loop {
+        buf.clear();
+        let num_bytes = handle.read_until(b'\n', &mut buf).expect("IO error");
+        if num_bytes == 0 { break; }
+
+        assert!(buf.len() >= 2);
+        assert_eq!((buf.len() - 1) % 2, 0);
+
+        let half_idx: usize = (buf.len() - 1) / 2;
+
+        let half_0: & [u8] = &(buf[0..half_idx]);
+        let half_1: & [u8] = &(buf[half_idx..buf.len()-1]);
+
+        let mut set_0: u64 = 0;
+        let mut set_1: u64 = 0;
+
+        for c in half_0 {
+            if *c <= 90 {
+                set_0 |= 1 << (*c - b'A');
+            }
+            else {
+                set_0 |= 1 << (*c - b'a' + 26);
+            }
+        }
+        for c in half_1 {
+            if *c <= 90 {
+                set_1 |= 1 << (*c - b'A');
+            }
+            else {
+                set_1 |= 1 << (*c - b'a' + 26);
+            }
+        }
+
+        let common: u64 = set_0 & set_1;
+        for i in 0..26 {
+            if common & (1 << i) != 0 {
+                result += 26 + i + 1;
+            }
+            if common & (1 << (26 + i)) != 0 {
+                result += i + 1;
+            }
+        }
+    }
+    println!("{}", result);
+}