Wrote program for Day 28

README.md

@@ -74,7 +74,7 @@ We encourage you to share your progress and ask questions in the Discussions sec
 | Day #25       | [Coin Trouble](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-25_Coin-Trouble)                          | :white_check_mark:      |
 | Day #26       | [Briefcase Lock](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-26_Briefcase-Lock)                        | :white_check_mark:      |
 | Day #27       | [Task Scheduler](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-27_Task-Scheduler)                        | :white_check_mark:      |
-| Day #28       | [Word Search](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-28_Word-Search)                           | :white_large_square:      |
+| Day #28       | [Word Search](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-04/Day-28_Word-Search)                           | :white_check_mark:      |
 | Day #29       | [Traffic Light Checker](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-05/Day-29_Traffic-Light-Checker)                 | :white_large_square:      |
 | Day #30       | [The Maximum Value](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-05/Day-30_The-Maximum-Value)                     | :white_large_square:      |
 | Day #31       | [The Time In Words](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-05/Day-31_The-Time-In-Words)                     | :white_large_square:      |

Week-04/Day-28_Word-Search/day28/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day28"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

Week-04/Day-28_Word-Search/day28/src/lib.rs

@@ -0,0 +1,72 @@
+use std::{char, collections::HashMap};
+
+pub fn word_search(board: &[Vec<char>], words: &[&str]) -> Vec<String> {
+    let mut first_char_to_word = HashMap::new();
+    for w in words {
+        first_char_to_word
+            .entry(w.chars().next().unwrap())
+            .or_insert(vec![])
+            .push(w);
+    }
+
+    let mut result = Vec::new();
+
+    for (rown, row) in board.iter().enumerate() {
+        for (column, ch) in row.iter().enumerate() {
+            if let Some(possible_words) = first_char_to_word.get(ch) {
+                for word in possible_words {
+                    if search(
+                        rown,
+                        column,
+                        board,
+                        &word.chars().skip(1).collect::<Vec<char>>(),
+                    ) {
+                        result.push(word.to_owned().to_owned().to_owned());
+                    }
+                }
+            }
+        }
+    }
+
+    result
+}
+
+fn search(row: usize, column: usize, board: &[Vec<char>], word: &[char]) -> bool {
+    if word.is_empty() {
+        return true;
+    }
+    let (first_char, other_chars) = word.split_first().unwrap();
+
+    if row > 0 {
+        if let Some(char_row) = board.get(row - 1) {
+            if char_row.get(column).unwrap() == first_char
+                && search(row - 1, column, board, other_chars)
+            {
+                return true;
+            }
+        }
+    }
+    if let Some(char_row) = board.get(row + 1) {
+        if char_row.get(column).unwrap() == first_char
+            && search(row + 1, column, board, other_chars)
+        {
+            return true;
+        }
+    }
+    if let Some(char_row) = board.get(row) {
+        if column > 0
+            && char_row.get(column - 1).unwrap() == first_char
+            && search(row, column - 1, board, other_chars)
+        {
+            return true;
+        }
+        if column + 1 < char_row.len()
+            && char_row.get(column + 1).unwrap() == first_char
+            && search(row, column + 1, board, other_chars)
+        {
+            return true;
+        }
+    }
+
+    false
+}

Week-04/Day-28_Word-Search/day28/src/main.rs

@@ -0,0 +1,40 @@
+use std::io::{self, Write};
+
+use day28::word_search;
+
+fn main() {
+    let mut buffer = String::new();
+    let mut board = Vec::new();
+
+    println!("Insert the characters of the rows without any space (press enter alone to stop creating the board): ");
+
+    loop {
+        print!("Row: ");
+        io::stdout().flush().expect("Failed to flush stdout");
+
+        io::stdin()
+            .read_line(&mut buffer)
+            .expect("Failed to read line");
+
+        if buffer.trim().is_empty() {
+            break;
+        }
+
+        board.push(buffer.trim().chars().collect());
+        buffer.clear();
+    }
+
+    buffer.clear();
+
+    print!("Insert the words separated by a space: ");
+    io::stdout().flush().expect("Failed to flush stdout");
+
+    io::stdin()
+        .read_line(&mut buffer)
+        .expect("Failed to read line");
+
+    let words: Vec<&str> = buffer.split_whitespace().collect();
+
+    let result = word_search(&board, &words);
+    println!("Words in the board: {:?}", result);
+}

Week-04/Day-28_Word-Search/day28/tests/example.rs

@@ -0,0 +1,20 @@
+#[cfg(test)]
+mod example {
+    use day28::word_search;
+
+    #[test]
+    fn example() {
+        assert_eq!(
+            word_search(
+                &[
+                    vec!['o', 'a', 'a', 'n'],
+                    vec!['e', 't', 'a', 'e'],
+                    vec!['i', 'h', 'k', 'r'],
+                    vec!['i', 'f', 'l', 'v']
+                ],
+                &["oath", "pea", "eat", "rain"]
+            ),
+            ["oath", "eat"]
+        )
+    }
+}