Add 2016 day 3

2016/src/bin/day3.rs

@@ -0,0 +1,58 @@
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::Path;
+
+fn parse_ints(line: String) -> Vec<i32> {
+    line.trim().split_whitespace().map(|p| p.parse::<i32>().unwrap()).collect::<Vec<_>>()
+}
+
+fn main() {
+    let path = Path::new("input.txt");
+    let display = path.display();
+
+    let mut file = match File::open(&path) {
+        Err(why) => panic!("couldn't open {}: {}", display, why),
+        Ok(file) => file,
+    };
+
+    let mut s = String::new();
+    file.read_to_string(&mut s).unwrap();
+
+    let lines = s.trim().split("\n");
+    let mut valid_triangles = 0;
+
+    for line in lines.clone() {
+        let mut parts = parse_ints(line.to_string());
+        parts.sort();
+
+        if parts[0] + parts[1] > parts[2] {
+            valid_triangles += 1;
+        }
+    }
+
+    println!("part 1 {}", valid_triangles);
+
+    valid_triangles = 0;
+
+    for line_group in lines.collect::<Vec<_>>().chunks(3) {
+        let mut triangles = vec!(Vec::new(), Vec::new(), Vec::new());
+
+        for line in line_group {
+            let parts = parse_ints(line.to_string());
+
+            for i in 0..3 {
+                triangles[i].push(parts[i]);
+            }
+        }
+
+        for i in 0..3 {
+            triangles[i].sort();
+
+            if triangles[i][0] + triangles[i][1] > triangles[i][2] {
+                valid_triangles += 1;
+            }
+        }
+    }
+
+    println!("part 2 {}", valid_triangles);
+}