solve 2016 day 03

src/year2016/day03.rs

@@ -1,13 +1,47 @@
 use crate::util::parse::ParseExt;
 
-pub fn part1(input: &str) -> impl std::fmt::Display {
+fn valid_triangle(v: &[u32; 3]) -> bool {
-    //let vec: Vec<Vec<u32>> = input.lines().map(|s| s.u32s().collect());
+    v[0] + v[1] > v[2] && v[1] + v[2] > v[0] && v[0] + v[2] > v[1]
+}
 
-    ""
+pub fn part1(input: &str) -> impl std::fmt::Display {
+    input
+        .lines()
+        .map(|s| {
+            s.u32s()
+                .fold(([0u32; 3], 0), |(mut a, i), v| {
+                    a[i] = v;
+                    (a, i + 1)
+                })
+                .0
+        })
+        .filter(valid_triangle)
+        .count()
 }
 
 pub fn part2(input: &str) -> impl std::fmt::Display {
-    ""
+    fn get3<'a>(lines: &'a mut std::str::Lines<'_>) -> Option<(&'a str, &'a str, &'a str)> {
+        Some((lines.next()?, lines.next()?, lines.next()?))
+    }
+
+    let mut lines = input.lines();
+    let mut valid = 0;
+
+    while let Some((l1, l2, l3)) = get3(&mut lines) {
+        let l1: Vec<u32> = l1.u32s().collect();
+        let l2: Vec<u32> = l2.u32s().collect();
+        let l3: Vec<u32> = l3.u32s().collect();
+        if valid_triangle(&[l1[0], l2[0], l3[0]]) {
+            valid += 1;
+        }
+        if valid_triangle(&[l1[1], l2[1], l3[1]]) {
+            valid += 1;
+        }
+        if valid_triangle(&[l1[2], l2[2], l3[2]]) {
+            valid += 1;
+        }
+    }
+    valid
 }
 
 #[test]