From fcd8eb2f6d40b9173b8129ff12208ec71a311f7d Mon Sep 17 00:00:00 2001
From: henine <why@no.com>
Date: Sun, 13 Dec 2020 10:53:13 +0100
Subject: [PATCH] day13

---
 day13/Cargo.toml  |  9 ++++++
 day13/input       |  2 ++
 day13/src/main.rs | 78 +++++++++++++++++++++++++++++++++++++++++++++++
 day13/test        |  2 ++
 4 files changed, 91 insertions(+)
 create mode 100644 day13/Cargo.toml
 create mode 100644 day13/input
 create mode 100644 day13/src/main.rs
 create mode 100644 day13/test

diff --git a/day13/Cargo.toml b/day13/Cargo.toml
new file mode 100644
index 0000000..f0447b8
--- /dev/null
+++ b/day13/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "day13"
+version = "0.1.0"
+authors = ["henine <why@no.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/day13/input b/day13/input
new file mode 100644
index 0000000..91abf0b
--- /dev/null
+++ b/day13/input
@@ -0,0 +1,2 @@
+1000104
+41,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,37,x,x,x,x,x,659,x,x,x,x,x,x,x,23,x,x,x,x,13,x,x,x,x,x,19,x,x,x,x,x,x,x,x,x,29,x,937,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,17
diff --git a/day13/src/main.rs b/day13/src/main.rs
new file mode 100644
index 0000000..086816b
--- /dev/null
+++ b/day13/src/main.rs
@@ -0,0 +1,78 @@
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+
+fn main() {
+    let file = File::open("input").unwrap();
+
+    let input_buffer = BufReader::new(&file);
+    let mut lines = input_buffer.lines();
+
+    let time: i64 = lines.next().unwrap().unwrap().parse().unwrap();
+    let (mut buses, mut counts, _): (Vec<i64>, Vec<i64>, i64) = lines.next().unwrap().unwrap()
+        .split(',')
+        .map(|num| match num.parse() {
+            Ok(num) => Some(num),
+            Err(_e) => None
+        })
+        .fold((Vec::new(), Vec::new(), 0),
+              |(mut ids, mut counts, count), id| match id {
+                  Some(id) => {
+                      ids.push(id);
+                      counts.push(count);
+                      (ids, counts, count + 1)
+                  }
+                  None => (ids, counts, count + 1)
+              });
+
+    println!("{}", time);
+    println!("{:?}", buses);
+    println!("{:?}", counts);
+
+    let mut i = 0;
+    loop {
+        if i == buses.len() - 1 { break; }
+        if buses[i + 1] > buses[i] {
+            buses.swap(i, i + 1);
+            counts.swap(i, i + 1);
+            if i > 0 { i -= 1 }
+        } else {
+            i += 1
+        }
+    }
+
+    println!("{:?}", buses);
+    println!("{:?}", counts);
+
+    let mut xi = (buses[0] - counts[0]).rem_euclid(buses[0]);
+
+    let mut prod_n = buses[0];
+
+    for i in 1..buses.len() {
+        let ai = (buses[i] - counts[i]).rem_euclid( buses[i]) ;
+        let ni = buses[i];
+
+
+        loop {
+            if xi % ni == ai { break; }
+            xi += prod_n;
+        }
+
+        prod_n *= ni;
+    }
+
+    println!("{}", xi);
+
+    // let mut min_time = *buses.iter().max().unwrap();
+    // let mut min_bus= 0;
+    // for bus_id in buses.iter()  {
+    //
+    //     let wait_time = bus_id-time%bus_id;
+    //
+    //     if wait_time < min_time {
+    //         min_time = wait_time;
+    //         min_bus = *bus_id;
+    //     }
+    // }
+    //
+    // println!("{}", min_bus*min_time);
+}
diff --git a/day13/test b/day13/test
new file mode 100644
index 0000000..e473080
--- /dev/null
+++ b/day13/test
@@ -0,0 +1,2 @@
+939
+7,13,x,x,59,x,31,19
\ No newline at end of file