20240310 Finished

src/problem/mod.rs

@@ -69,3 +69,4 @@ mod p2917_find_the_k_or_of_an_array;
 mod p2575_find_the_divisibility_array_of_a_string;
 mod p2834_find_the_minimum_possible_sum_of_a_beautiful_array;
 mod p2386_find_the_k_sum_of_an_array;
+mod p299_bulls_and_cows;

src/problem/p299_bulls_and_cows.rs

@@ -0,0 +1,55 @@
+/**
+ * [299] Bulls and Cows
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+use std::collections::HashMap;
+
+impl Solution {
+    pub fn get_hint(secret: String, guess: String) -> String {
+        let secret: Vec<char> = secret.chars().collect();
+        let guess: Vec<char> = guess.chars().collect();
+
+        let mut bull = 0;
+        let mut cow_map = HashMap::new();
+        let mut cow_candidate = Vec::with_capacity(guess.len());
+
+        for i in 0..secret.len() {
+            if secret[i] == guess[i] {
+                bull += 1;
+            } else {
+                let entry = cow_map.entry(secret[i]).or_insert(0);
+                *entry += 1;
+
+                cow_candidate.push(guess[i]);
+            }
+        }
+
+        let mut cow = 0;
+        for candidate in cow_candidate {
+            if let Some(entry) = cow_map.get_mut(&candidate) {
+                if *entry != 0 {
+                    cow += 1;
+                    *entry -= 1;
+                }
+            }
+        }
+
+        format!("{}A{}B", bull, cow)
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_299() {
+        assert_eq!("1A3B", Solution::get_hint("1807".to_owned(), "7810".to_owned()));
+        assert_eq!("1A1B", Solution::get_hint("1123".to_owned(), "0111".to_owned()));
+    }
+}