Add problem 2347: Best Poker Hand

src/lib.rs

@@ -1738,6 +1738,7 @@ pub mod problem_2336_smallest_number_in_infinite_set;
 pub mod problem_2337_move_pieces_to_obtain_a_string;
 pub mod problem_2341_maximum_number_of_pairs_in_array;
 pub mod problem_2342_max_sum_of_a_pair_with_equal_sum_of_digits;
+pub mod problem_2347_best_poker_hand;
 
 #[cfg(test)]
 mod test_utilities;

src/problem_2347_best_poker_hand/brute_force.rs

@@ -0,0 +1,60 @@
+pub struct Solution;
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl Solution {
+    fn helper(ranks: &[i32; 5], suits: &[char; 5]) -> &'static str {
+        let first_suit = suits[0];
+
+        if suits[1..].iter().all(|&suit| suit == first_suit) {
+            return "Flush";
+        }
+
+        let mut counts = [0_u8; 13];
+        let mut ranks_iter = ranks.iter().copied();
+
+        while let Some(rank) = ranks_iter.next() {
+            let count = &mut counts[(rank as usize).wrapping_sub(1)];
+
+            *count += 1;
+
+            if *count == 2 {
+                for rank in ranks_iter {
+                    let count = &mut counts[(rank as usize).wrapping_sub(1)];
+
+                    if *count == 2 {
+                        return "Three of a Kind";
+                    }
+
+                    *count += 1;
+                }
+
+                return "Pair";
+            }
+        }
+
+        "High Card"
+    }
+
+    pub fn best_hand(ranks: Vec<i32>, suits: Vec<char>) -> String {
+        let (ranks, suits) = Option::zip(ranks.as_slice().try_into().ok(), suits.as_slice().try_into().ok()).unwrap();
+
+        Self::helper(ranks, suits).to_string()
+    }
+}
+
+// ------------------------------------------------------ snip ------------------------------------------------------ //
+
+impl super::Solution for Solution {
+    fn best_hand(ranks: Vec<i32>, suits: Vec<char>) -> String {
+        Self::best_hand(ranks, suits)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_solution() {
+        super::super::tests::run::<super::Solution>();
+    }
+}

src/problem_2347_best_poker_hand/mod.rs

@@ -0,0 +1,23 @@
+pub mod brute_force;
+
+pub trait Solution {
+    fn best_hand(ranks: Vec<i32>, suits: Vec<char>) -> String;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    pub fn run<S: Solution>() {
+        let test_cases = [
+            (([13, 2, 3, 1, 9], "aaaaa"), "Flush"),
+            (([4, 4, 2, 4, 4], "daabc"), "Three of a Kind"),
+            (([10, 10, 2, 12, 9], "abcad"), "Pair"),
+            (([13, 12, 3, 4, 7], "adcbc"), "High Card"),
+        ];
+
+        for ((ranks, suits), expected) in test_cases {
+            assert_eq!(S::best_hand(ranks.to_vec(), suits.chars().collect()), expected);
+        }
+    }
+}