Day 7

1 files changed, 27 insertions, 0 deletions

diff --git a/07/src/part-1.rs b/07/src/part-1.rs
new file mode 100644
index 0000000..db20c41
--- /dev/null
+++ b/07/src/part-1.rs
@@ -0,0 +1,27 @@
+use std::io::{BufRead};
+
+fn cost(positions: & [i64], dest: i64) -> i64 {
+    positions.into_iter().map(|x| (x - dest).abs()).sum()
+}
+
+fn median<T: Copy + Ord>(mut x: Vec<T>) -> T {
+    let n = x.len();
+    *x.select_nth_unstable(n/2).1
+}
+
+pub fn main() {
+    let mut stdin = std::io::stdin();
+    let mut handle = stdin.lock();
+
+    let input: String = {
+        let mut buf = String::new();
+        handle.read_line(&mut buf).unwrap();
+        String::from(buf.trim_end())
+    };
+
+    let positions: Vec<i64> = input.split(',').map(|w| w.parse().expect("Malformed input")).collect();
+    let median = median(positions.clone());
+    let cost = cost(& positions, median);
+    
+    println!("Align at {} for a cost of {}.", median, cost);
+}