2017/06-07

2017/06/Cargo.lock

@@ -0,0 +1,4 @@
+[[package]]
+name = "day-06"
+version = "0.1.0"
+

2017/06/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day-06"
+version = "0.1.0"
+authors = ["logaritmisk <anders.e.olsson@gmail.com>"]
+
+[dependencies]

2017/06/input.txt

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+4	10	4	1	8	4	9	14	5	1	14	15	0	15	3	5

2017/06/src/main.rs

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+use std::io::{self, Read};
+use std::collections::HashSet;
+
+
+fn parse(input: &str) -> Vec<u16> {
+    input.split_whitespace().flat_map(str::parse).collect()
+}
+
+fn cycle(input: &mut [u16]) {
+    let (index, blocks) = input
+        .iter()
+        .enumerate()
+        .fold((0, 0), |acc, (index, blocks)| {
+            if *blocks > acc.1 {
+                (index, *blocks)
+            } else {
+                acc
+            }
+        });
+
+    input[index] = 0;
+
+    let len = input.len();
+
+    for i in 0..blocks as usize {
+        input[(index + i + 1) % len] += 1;
+    }
+}
+
+fn infinit_loop(mut memory: Vec<u16>) -> (Vec<u16>, usize) {
+    let mut states = HashSet::new();
+
+    states.insert(memory.clone());
+
+    let mut i = 0;
+
+    loop {
+        i += 1;
+
+        cycle(&mut memory);
+
+        if states.contains(&memory) {
+            break;
+        }
+
+        states.insert(memory.clone());
+    }
+
+    (memory, i)
+}
+
+fn main() {
+    let mut input = String::new();
+
+    io::stdin()
+        .read_to_string(&mut input)
+        .expect("faild to read input");
+
+    for entry in input.lines().filter(|line| !line.is_empty()).map(parse) {
+        let (state, cycle) = infinit_loop(entry);
+
+        println!("part_one={}", cycle);
+
+        let (_, cycle) = infinit_loop(state);
+
+        println!("part_two={}", cycle);
+    }
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse() {
+        assert_eq!(parse("0 2 7 0"), vec![0, 2, 7, 0]);
+    }
+
+    #[test]
+    fn test_cycle() {
+        let mut data = vec![0, 2, 7, 0];
+
+        cycle(&mut data);
+
+        assert_eq!(data, vec![2, 4, 1, 2]);
+    }
+
+    #[test]
+    fn test_infinit_loop() {
+        let data = vec![0, 2, 7, 0];
+
+        let (state, cycle) = infinit_loop(data);
+
+        assert_eq!(cycle, 5);
+
+        let (_, cycle) = infinit_loop(state);
+
+        assert_eq!(cycle, 4);
+    }
+}