Add src/06part1.rs

src/06part1.rs

@@ -0,0 +1,29 @@
+use std::fs;
+
+fn main() {
+    let file_path = "input/06input.txt";
+    let contents = fs::read_to_string(file_path).expect("should read file");
+    let mut lines = contents.lines();
+    let time_str = lines.next().unwrap().strip_prefix("Time:      ").unwrap();
+    let times: Vec<u128> = time_str.split_whitespace().map(|x| x.parse::<u128>().ok().unwrap()).collect();
+    let distance_str = lines.next().unwrap().strip_prefix("Distance:  ").unwrap();
+    let distances: Vec<u128> = distance_str.split_whitespace().map(|x| x.parse::<u128>().ok().unwrap()).collect();
+    let mut total = 1;
+    for i in 0..times.len() {
+        let mut j = 0;
+        let mut k = times[i]-1;
+        loop {
+            if j*(times[i]-j) <= distances[i] {
+                j += 1;
+            }
+            if k*(times[i]-k) <= distances[i] {
+                k -= 1;
+            }
+            if j*(times[i]-j) > distances[i] && k*(times[i]-k) > distances[i] {
+                total *= k - j + 1;
+                break;
+            }
+        }
+    }
+    println!("{}", total);
+}