Wrote program for Day12

README.md

@@ -58,7 +58,7 @@ We encourage you to share your progress and ask questions in the Discussions sec
 | Day #9        | [Trapping Rain Water](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-09_Trapping-Rain-Water)                   | :white_check_mark:      |
 | Day #10       | [Unique Binary Search Tree](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-10_Unique-Binary-Search-Trees)             | :white_check_mark:      |
 | Day #11       | [Restore IP Addresses](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-11_Restore-IP-Addresses)                  | :white_check_mark:      |
-| Day #12       | [Mountains or Valleys](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-12_Mountains_And_Valleys)                  | :white_large_square:      |
+| Day #12       | [Mountains or Valleys](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-12_Mountains_And_Valleys)                  | :white_check_mark:      |
 | Day #13       | [Need Help With Your Packing](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-13_Need-Help-With-Packing)           | :white_large_square:      |
 | Day #14       | [The Karacas Encryption Algorithm](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-02/Day-14_Karacas-Encryption-Algorithm)      | :white_large_square:      |
 | Day #15       | [Valid Anagram](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-03/Day-15_Valid-Anagram)                         | :white_large_square:      |

Week-02/Day-12_Mountains_And_Valleys/day12/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day12"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

Week-02/Day-12_Mountains_And_Valleys/day12/src/lib.rs

@@ -0,0 +1,69 @@
+pub enum LandscapeType {
+    Mountain,
+    Valley,
+    Neither,
+}
+
+fn is_mountain(numbers: &[isize], max: (usize, &isize)) -> bool {
+    if max.0 > 0 && max.0 < numbers.len() - 1 {
+        for (i, n) in numbers[1..max.0].iter().enumerate() {
+            if numbers[i] > *n {
+                return false;
+            }
+        }
+        for (i, n) in numbers[1 + max.0..numbers.len() - 1].iter().enumerate() {
+            if *n > numbers[max.0 + i] {
+                return false;
+            }
+        }
+
+        true
+    } else {
+        false
+    }
+}
+
+fn is_valley(numbers: &[isize], min: (usize, &isize)) -> bool {
+    if min.0 > 0 && min.0 < numbers.len() - 1 {
+        for (i, n) in numbers[1..min.0].iter().enumerate() {
+            if numbers[i] < *n {
+                return false;
+            }
+        }
+        for (i, n) in numbers[1 + min.0..numbers.len()].iter().enumerate() {
+            if *n < numbers[min.0 + i] {
+                return false;
+            }
+        }
+
+        true
+    } else {
+        false
+    }
+}
+
+pub fn landscape_type(numbers: &[isize]) -> LandscapeType {
+    if numbers.is_empty() {
+        return LandscapeType::Neither;
+    }
+
+    let mut min = (usize::MAX, &isize::MAX);
+    let mut max = (usize::MIN, &isize::MIN);
+
+    for (i, n) in numbers.iter().enumerate() {
+        if n < min.1 {
+            min = (i, n);
+        }
+        if n > max.1 {
+            max = (i, n);
+        }
+    }
+
+    if is_mountain(numbers, max) {
+        LandscapeType::Mountain
+    } else if is_valley(numbers, min) {
+        LandscapeType::Valley
+    } else {
+        LandscapeType::Neither
+    }
+}

Week-02/Day-12_Mountains_And_Valleys/day12/src/main.rs

@@ -0,0 +1,32 @@
+use std::io::{self, Write};
+
+use day12::landscape_type;
+
+fn main() {
+    let mut buffer = String::new();
+
+    print!("Insert space separated numbers: ");
+    io::stdout().flush().expect("Failed to flush stdout.");
+
+    io::stdin()
+        .read_line(&mut buffer)
+        .expect("Failed to read from input");
+
+    let numbers: Vec<isize> = buffer
+        .trim()
+        .split(' ')
+        .filter(|x| !x.is_empty())
+        .map(|x| {
+            x.parse()
+                .expect("Error: Please enter numbers separated by spaces, e.g. 1 2 3")
+        })
+        .collect();
+
+    let result = match landscape_type(&numbers) {
+        day12::LandscapeType::Mountain => "Mountain",
+        day12::LandscapeType::Valley => "Valley",
+        day12::LandscapeType::Neither => "Neither",
+    };
+
+    println!("{}", result);
+}

Week-02/Day-12_Mountains_And_Valleys/day12/tests/examples.rs

@@ -0,0 +1,30 @@
+use day12::{landscape_type, LandscapeType};
+
+#[test]
+fn example1() {
+    assert!(matches!(
+        landscape_type(&[3, 4, 5, 4, 3]),
+        LandscapeType::Mountain
+    ))
+}
+
+#[test]
+fn example2() {
+    assert!(matches!(
+        landscape_type(&[9, 7, 3, 1, 2, 4]),
+        LandscapeType::Valley
+    ))
+}
+
+#[test]
+fn example3() {
+    assert!(matches!(landscape_type(&[9, 8, 9]), LandscapeType::Valley))
+}
+
+#[test]
+fn example4() {
+    assert!(matches!(
+        landscape_type(&[9, 8, 9, 8]),
+        LandscapeType::Neither
+    ))
+}