Added AOC 2020 day 21 - 25

www/statics/aoc/2020/23_solution.rs

@@ -0,0 +1,135 @@
+use crate::common::AdventOfCodeDay;
+
+pub struct Day23 {
+    input: Vec<u8>,
+}
+
+impl Day23 {
+    pub fn new() -> Self {
+        let input_bytes = include_bytes!("../res/23_input.txt");
+        let input_str = String::from_utf8_lossy(input_bytes);
+        
+        let cups = input_str
+                        .chars()
+                        .map(|p| p.to_string().parse::<u8>().unwrap())
+                        .collect::<Vec<u8>>();
+
+        Self {
+            input: cups
+        }
+    }
+}
+
+impl Day23 {
+    fn do_move(cups: &mut Vec<u8>) {
+
+        verboseln!("Cups: {:?}", cups);
+
+        let n1 = cups[1];
+        let n2 = cups[2];
+        let n3 = cups[3];
+
+        verboseln!("pick up: {}, {}, {}", n1,n2,n3);
+
+        let mut dest = (cups[0] + 9-1-1) % 9 + 1;
+        while !cups.iter().skip(4).any(|p| *p == dest) {
+            dest = (dest + 9-1-1) % 9 + 1;
+        }
+        let dest_idx = cups.iter().position(|p| *p==dest).unwrap() + 1;
+
+        verboseln!("destination: {}, (idx: {})", dest,dest_idx);
+
+        cups.insert(dest_idx, n3);
+        cups.insert(dest_idx, n2);
+        cups.insert(dest_idx, n1);
+
+        cups.remove(1);
+        cups.remove(1);
+        cups.remove(1);
+        
+        let f = cups.remove(0);
+        cups.push(f);
+
+        verboseln!();
+    }
+
+    fn do_move_linkedlist(cups: &mut [u32; 1_000_000], currcup: u32) -> u32 {
+        let n0 = currcup;
+        let n1 = cups[n0 as usize];
+        let n2 = cups[n1 as usize];
+        let n3 = cups[n2 as usize];
+        let n4 = cups[n3 as usize];
+
+        let mut dest = (n0+(1_000_000-1)) % 1_000_000;
+        while dest == n1 || dest == n2 || dest == n3 {
+            dest = (dest+(1_000_000-1)) % 1_000_000;
+        }
+
+        let d1 = cups[dest as usize];
+
+        //verboseln!("Cups [ptr]: {:?}", cups.iter().take(16).collect::<Vec<_>>());
+        //verboseln!("current: {}", currcup);
+        //verboseln!("picked: {},{},{}", n1,n2,n3);
+        //verboseln!("destination: {}", dest);
+
+        // remove after curr
+        cups[n0 as usize]   = n4;
+
+        // insert after dest
+        cups[dest as usize] = n1;
+        cups[n3 as usize]   = d1;
+
+        return n4;
+    }
+}
+
+impl AdventOfCodeDay for Day23 {
+
+    fn task_1(&self) -> String {
+
+        let mut cups = self.input.clone();
+
+        for _ in 0..100 {
+            Self::do_move(&mut cups);
+        }
+
+        let c1idx = cups.iter().position(|p| *p==1).unwrap();
+        
+        let mut r = String::new();
+        for idx in 1..9 {
+            r = r + &cups[(idx+c1idx) % 9].to_string();
+        }
+
+        return r;
+    }
+
+    
+    fn task_2(&self) -> String  {
+        let mut cups = [0u32; 1_000_000]; // at cell[x] is the value of the cup right to the cup with the value x  (-> single-linked-list)
+
+        for idx in 0..1_000_000 {
+            if idx == (1_000_000-1) {
+                cups[idx] = (self.input[0]-1) as u32;
+            } else if idx > 8 {
+                cups[idx] = (idx+1) as u32;
+            } else if idx == 8 {
+                cups[(self.input[idx]-1) as usize] = 9;
+            } else {
+                cups[(self.input[idx]-1) as usize] = (self.input[idx+1 as usize]-1) as u32;
+            }
+        }
+
+        let mut curr = (self.input[0]-1) as u32;
+        for _ in 0..10_000_000 {
+            curr = Self::do_move_linkedlist(&mut cups, curr);
+        }
+
+        let n1 = cups[0 as usize]  as u128;
+        let n2 = cups[n1 as usize] as u128;
+
+        verboseln!("{} * {}", n1+1, n2+1);
+
+        return ((n1+1)*(n2+1)).to_string();
+    }
+    
+}