Day 17b done

src/day17.rs

@@ -1,6 +1,6 @@
 use std::io;
 
-fn find_min_heat_loss(board: &Vec<Vec<u64>>) -> u64 {
+fn find_min_heat_loss(board: &Vec<Vec<u64>>, min_move: usize, max_move: usize) -> u64 {
   let mut horiz_min: Vec<Vec<u64>> = Vec::new();
   let mut vert_min: Vec<Vec<u64>> = Vec::new();
 
@@ -19,29 +19,28 @@ fn find_min_heat_loss(board: &Vec<Vec<u64>>) -> u64 {
     for r in 0..board.len() {
       for c in 0..board[r].len() {
         let prev = horiz_min[r][c];
+
         // Check Backwards.
-        if c > 0 && vert_min[r][c - 1] != u64::MAX {
+        let mut sum_back = 0;
-          horiz_min[r][c] = horiz_min[r][c].min(vert_min[r][c - 1] + board[r][c - 1]);
+        let mut m = 1;
-        }
+        while m <= max_move && c >= m {
-        if c > 1 && vert_min[r][c - 2] != u64::MAX {
+          sum_back += board[r][c - m];
-          horiz_min[r][c] =
+          if m >= min_move && vert_min[r][c - m] != u64::MAX {
-            horiz_min[r][c].min(vert_min[r][c - 2] + board[r][c - 1] + board[r][c - 2]);
+            horiz_min[r][c] = horiz_min[r][c].min(vert_min[r][c - m] + sum_back);
-        }
+          }
-        if c > 2 && vert_min[r][c - 3] != u64::MAX {
+
-          horiz_min[r][c] = horiz_min[r][c]
+          m += 1;
-            .min(vert_min[r][c - 3] + board[r][c - 1] + board[r][c - 2] + board[r][c - 3]);
         }
+
         // Check Forwards.
-        if c < board[r].len() - 1 && vert_min[r][c + 1] != u64::MAX {
+        let mut sum_forwards = 0;
-          horiz_min[r][c] = horiz_min[r][c].min(vert_min[r][c + 1] + board[r][c + 1]);
+        let mut m = 1;
-        }
+        while m <= max_move && c + m < board[r].len() {
-        if c < board[r].len() - 2 && vert_min[r][c + 2] != u64::MAX {
+          sum_forwards += board[r][c + m];
-          horiz_min[r][c] =
+          if m >= min_move && vert_min[r][c + m] != u64::MAX {
-            horiz_min[r][c].min(vert_min[r][c + 2] + board[r][c + 1] + board[r][c + 2]);
+            horiz_min[r][c] = horiz_min[r][c].min(vert_min[r][c + m] + sum_forwards);
-        }
+          }
-        if c < board[r].len() - 3 && vert_min[r][c + 3] != u64::MAX {
+          m += 1;
-          horiz_min[r][c] = horiz_min[r][c]
-            .min(vert_min[r][c + 3] + board[r][c + 1] + board[r][c + 2] + board[r][c + 3]);
         }
 
         if horiz_min[r][c] != prev {
@@ -54,30 +53,28 @@ fn find_min_heat_loss(board: &Vec<Vec<u64>>) -> u64 {
     for r in 0..board.len() {
       for c in 0..board[r].len() {
         let prev = vert_min[r][c];
-        // Check Backwards
+
-        if r > 0 && horiz_min[r - 1][c] != u64::MAX {
+        // Check Backwards.
-          vert_min[r][c] = vert_min[r][c].min(horiz_min[r - 1][c] + board[r - 1][c]);
+        let mut sum_back = 0;
-        }
+        let mut m = 1;
-        if r > 1 && horiz_min[r - 2][c] != u64::MAX {
+        while m <= max_move && r >= m {
-          vert_min[r][c] =
+          sum_back += board[r - m][c];
-            vert_min[r][c].min(horiz_min[r - 2][c] + board[r - 1][c] + board[r - 2][c]);
+          if m >= min_move && horiz_min[r - m][c] != u64::MAX {
-        }
+            vert_min[r][c] = vert_min[r][c].min(horiz_min[r - m][c] + sum_back);
-        if r > 2 && horiz_min[r - 3][c] != u64::MAX {
+          }
-          vert_min[r][c] = vert_min[r][c]
+
-            .min(horiz_min[r - 3][c] + board[r - 1][c] + board[r - 2][c] + board[r - 3][c]);
+          m += 1;
         }
 
         // Check Forwards.
-        if r < board.len() - 1 && horiz_min[r + 1][c] != u64::MAX {
+        let mut sum_forwards = 0;
-          vert_min[r][c] = vert_min[r][c].min(horiz_min[r + 1][c] + board[r + 1][c]);
+        let mut m = 1;
-        }
+        while m <= max_move && r + m < board.len() {
-        if r < board.len() - 2 && horiz_min[r + 2][c] != u64::MAX {
+          sum_forwards += board[r + m][c];
-          vert_min[r][c] =
+          if m >= min_move && horiz_min[r + m][c] != u64::MAX {
-            vert_min[r][c].min(horiz_min[r + 2][c] + board[r + 1][c] + board[r + 2][c]);
+            vert_min[r][c] = vert_min[r][c].min(horiz_min[r + m][c] + sum_forwards);
-        }
+          }
-        if r < board.len() - 3 && horiz_min[r + 3][c] != u64::MAX {
+          m += 1;
-          vert_min[r][c] = vert_min[r][c]
-            .min(horiz_min[r + 3][c] + board[r + 1][c] + board[r + 2][c] + board[r + 3][c]);
         }
 
         if vert_min[r][c] != prev {
@@ -94,7 +91,7 @@ fn find_min_heat_loss(board: &Vec<Vec<u64>>) -> u64 {
   horiz_min[0][0].min(vert_min[0][0])
 }
 
-pub fn min_heat_loss() -> u64 {
+pub fn min_heat_loss(min_move: usize, max_move: usize) -> u64 {
   let mut buffer = String::new();
 
   while io::stdin().read_line(&mut buffer).unwrap() > 0 {}
@@ -105,5 +102,5 @@ pub fn min_heat_loss() -> u64 {
     .map(|s| s.chars().map(|c| (c as u64 - '0' as u64)).collect())
     .collect();
 
-  find_min_heat_loss(&board)
+  find_min_heat_loss(&board, min_move, max_move)
 }

src/main.rs

@@ -57,7 +57,8 @@ fn main() {
     "day15b" => println!("Sum: {}", day15::hash_map()),
     "day16a" => println!("Answer: {}", day16::solve()),
     "day16b" => println!("Answer: {}", day16::find_best()),
-    "day17a" => println!("Minimum: {}", day17::min_heat_loss()),
+    "day17a" => println!("Minimum: {}", day17::min_heat_loss(1, 3)),
+    "day17b" => println!("Minimum: {}", day17::min_heat_loss(4, 10)),
     _ => println!("Unrecognized day: {}", args[1]),
   }
 }