pad numbers on directory names

day08/src/main.rs

@@ -0,0 +1,56 @@
+use std::env;
+use std::fs;
+
+fn main() {
+    let input = fs::read_to_string(&env::args().nth(1).unwrap()).unwrap();
+    let forest: Vec<Vec<i8>> = input.lines()
+        .map(|line| line.chars()
+            .map(|c| c.to_digit(10).unwrap() as i8).collect())
+        .collect();
+    let nrows = forest.len();
+    let ncols = forest[0].len();
+
+    let mut scores = vec![vec![1; ncols]; nrows];
+    for r in 1..nrows-1 {
+        for c in 1..ncols-1 {
+            let h = forest[r][c];
+
+            let mut j = c - 1;
+            let mut count = 0;
+            while j > 0 && forest[r][j] < h {
+                count += 1;
+                j -= 1;
+            }
+            scores[r][c] *= count + 1;
+
+            let mut j = c + 1;
+            let mut count = 0;
+            while j < ncols-1 && forest[r][j] < h {
+                count += 1;
+                j += 1;
+            }
+            scores[r][c] *= count + 1;
+
+            let mut i = r - 1;
+            let mut count = 0;
+            while i > 0 && forest[i][c] < h {
+                count += 1;
+                i -= 1;
+            }
+            scores[r][c] *= count + 1;
+
+            let mut i = r + 1;
+            let mut count = 0;
+            while i < nrows-1 && forest[i][c] < h {
+                count += 1;
+                i += 1;
+            }
+            scores[r][c] *= count + 1;
+
+        }
+    }
+
+    let answer = scores.iter().map(|row| row.iter().max()).max();
+    println!("{:?}", answer);
+}
+

day08/src/main1.rs

@@ -0,0 +1,59 @@
+use std::env;
+use std::fs;
+
+fn main() {
+    let input = fs::read_to_string(&env::args().nth(1).unwrap()).unwrap();
+    let forest: Vec<Vec<i8>> = input.lines()
+        .map(|line| line.chars()
+            .map(|c| c.to_digit(10).unwrap() as i8).collect())
+        .collect();
+    let nrows = forest.len();
+    let ncols = forest[0].len();
+
+    let min_from_left: Vec<Vec<i8>> = forest.iter()
+        .map(|row| row.iter()
+            .scan(-1, |h, &tree| {
+                let old = *h; *h = i8::max(*h as i8, tree); Some(old)
+            })
+            .collect())
+        .collect();
+
+    let min_from_right: Vec<Vec<i8>> = forest.iter()
+        .map(|row: &Vec<i8>| row.iter()
+            .rev()
+            .scan(-1, |h, &tree| {
+                let old = *h; *h = i8::max(*h as i8, tree); Some(old)
+            })
+            .collect::<Vec<i8>>().iter()
+            .rev().map(|x| *x)
+            .collect())
+        .collect();
+
+    let mut min_from_top: Vec<Vec<i8>> = vec![vec![-1; ncols]; nrows];
+    for c in 0..ncols {
+        for r in 1..nrows {
+            min_from_top[r][c] = i8::max(min_from_top[r-1][c], forest[r-1][c]);
+        }
+    } 
+
+    let mut min_from_bot: Vec<Vec<i8>> = vec![vec![-1; ncols]; nrows];
+    for c in 0..ncols {
+        for r in (0..nrows-1).rev() {
+            min_from_bot[r][c] = i8::max(min_from_bot[r+1][c], forest[r+1][c]);
+        }
+    } 
+
+    let mut sum = 0;
+    for r in 0..nrows {
+        for c in 0..ncols {
+            if forest[r][c] > min_from_left[r][c]
+                || forest[r][c] > min_from_right[r][c]
+                || forest[r][c] > min_from_top[r][c]
+                || forest[r][c] > min_from_bot[r][c] {
+                sum += 1;
+            }
+        }
+    }
+    println!("{:?}", sum);
+}
+