1535. Find the Winner of an Array Game: AC

Author: tan-wei

src/solution/mod.rs

@@ -1157,3 +1157,4 @@ mod s1529_minimum_suffix_flips;
 mod s1530_number_of_good_leaf_nodes_pairs;
 mod s1531_string_compression_ii;
 mod s1534_count_good_triplets;
+mod s1535_find_the_winner_of_an_array_game;

src/solution/s1535_find_the_winner_of_an_array_game.rs

@@ -0,0 +1,91 @@
+/**
+ * [1535] Find the Winner of an Array Game
+ *
+ * Given an integer array arr of distinct integers and an integer k.
+ * A game will be played between the first two elements of the array (i.e. arr[0] and arr[1]). In each round of the game, we compare arr[0] with arr[1], the larger integer wins and remains at position 0, and the smaller integer moves to the end of the array. The game ends when an integer wins k consecutive rounds.
+ * Return the integer which will win the game.
+ * It is guaranteed that there will be a winner of the game.
+ *  
+ * Example 1:
+ *
+ * Input: arr = [2,1,3,5,4,6,7], k = 2
+ * Output: 5
+ * Explanation: Let's see the rounds of the game:
+ * Round |       arr       | winner | win_count
+ *   1   | [2,1,3,5,4,6,7] | 2      | 1
+ *   2   | [2,3,5,4,6,7,1] | 3      | 1
+ *   3   | [3,5,4,6,7,1,2] | 5      | 1
+ *   4   | [5,4,6,7,1,2,3] | 5      | 2
+ * So we can see that 4 rounds will be played and 5 is the winner because it wins 2 consecutive games.
+ *
+ * Example 2:
+ *
+ * Input: arr = [3,2,1], k = 10
+ * Output: 3
+ * Explanation: 3 will win the first 10 rounds consecutively.
+ *
+ *  
+ * Constraints:
+ *
+ * 	2 <= arr.length <= 10^5
+ * 	1 <= arr[i] <= 10^6
+ * 	arr contains distinct integers.
+ * 	1 <= k <= 10^9
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/find-the-winner-of-an-array-game/
+// discuss: https://leetcode.com/problems/find-the-winner-of-an-array-game/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn get_winner(arr: Vec<i32>, k: i32) -> i32 {
+        let mut result = arr[0];
+        if k == 1 {
+            result.max(arr[1])
+        } else {
+            arr.iter().try_fold(-1, |c, &x| {
+                if x > result {
+                    result = x;
+                    Some(1)
+                } else {
+                    if c + 1 == k {
+                        None
+                    } else {
+                        Some(c + 1)
+                    }
+                }
+            });
+            result
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1535_example_1() {
+        let arr = vec![2, 1, 3, 5, 4, 6, 7];
+        let k = 2;
+
+        let result = 5;
+
+        assert_eq!(Solution::get_winner(arr, k), result);
+    }
+
+    #[test]
+    fn test_1535_example_2() {
+        let arr = vec![3, 2, 1];
+        let k = 10;
+
+        let result = 3;
+
+        assert_eq!(Solution::get_winner(arr, k), result);
+    }
+}