1945. Sum of Digits of String After Convert: AC

Author: tan-wei

Diff for: src/solution/mod.rs

@@ -1466,3 +1466,4 @@ mod s1941_check_if_all_characters_have_equal_number_of_occurrences;
 mod s1942_the_number_of_the_smallest_unoccupied_chair;
 mod s1943_describe_the_painting;
 mod s1944_number_of_visible_people_in_a_queue;
+mod s1945_sum_of_digits_of_string_after_convert;

Diff for: src/solution/s1945_sum_of_digits_of_string_after_convert.rs

@@ -0,0 +1,114 @@
+/**
+ * [1945] Sum of Digits of String After Convert
+ *
+ * You are given a string s consisting of lowercase English letters, and an integer k. Your task is to convert the string into an integer by a special process, and then transform it by summing its digits repeatedly k times. More specifically, perform the following steps:
+ * <ol>
+ * 	Convert s into an integer by replacing each letter with its position in the alphabet (i.e. replace 'a' with 1, 'b' with 2, ..., 'z' with 26).
+ * 	Transform the integer by replacing it with the sum of its digits.
+ * 	Repeat the transform operation (step 2) k times in total.
+ * </ol>
+ * For example, if s = "zbax" and k = 2, then the resulting integer would be 8 by the following operations:
+ * <ol>
+ * 	Convert: "zbax" ➝ "(26)(2)(1)(24)" ➝ "262124" ➝ 262124
+ * 	Transform #1: 262124 ➝ 2 + 6 + 2 + 1 + 2 + 4 ➝ 17
+ * 	Transform #2: 17 ➝ 1 + 7 ➝ 8
+ * </ol>
+ * Return the resulting integer after performing the operations described above.
+ *  
+ * Example 1:
+ * <div class="example-block">
+ * Input: <span class="example-io">s = "iiii", k = 1</span>
+ * Output: <span class="example-io">36</span>
+ * Explanation:
+ * The operations are as follows:<br />
+ * - Convert: "iiii" ➝ "(9)(9)(9)(9)" ➝ "9999" ➝ 9999<br />
+ * - Transform #1: 9999 ➝ 9 + 9 + 9 + 9 ➝ 36<br />
+ * Thus the resulting integer is 36.
+ * </div>
+ * Example 2:
+ * <div class="example-block">
+ * Input: <span class="example-io">s = "leetcode", k = 2</span>
+ * Output: <span class="example-io">6</span>
+ * Explanation:
+ * The operations are as follows:<br />
+ * - Convert: "leetcode" ➝ "(12)(5)(5)(20)(3)(15)(4)(5)" ➝ "12552031545" ➝ 12552031545<br />
+ * - Transform #1: 12552031545 ➝ 1 + 2 + 5 + 5 + 2 + 0 + 3 + 1 + 5 + 4 + 5 ➝ 33<br />
+ * - Transform #2: 33 ➝ 3 + 3 ➝ 6<br />
+ * Thus the resulting integer is 6.
+ * </div>
+ * Example 3:
+ * <div class="example-block">
+ * Input: <span class="example-io">s = "zbax", k = 2</span>
+ * Output: <span class="example-io">8</span>
+ * </div>
+ *  
+ * Constraints:
+ *
+ * 	1 <= s.length <= 100
+ * 	1 <= k <= 10
+ * 	s consists of lowercase English letters.
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/sum-of-digits-of-string-after-convert/
+// discuss: https://leetcode.com/problems/sum-of-digits-of-string-after-convert/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn get_lucky(s: String, k: i32) -> i32 {
+        let mut s = s
+            .chars()
+            .map(|c| (c as u8 - b'a' + 1).to_string())
+            .collect::<Vec<String>>()
+            .join("");
+
+        for _ in 0..k {
+            s = s
+                .chars()
+                .map(|c| c as i32 - '0' as i32)
+                .sum::<i32>()
+                .to_string();
+        }
+
+        s.parse::<i32>().unwrap()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1945_example_1() {
+        let s = "iiii".to_string();
+        let k = 1;
+
+        let result = 36;
+
+        assert_eq!(Solution::get_lucky(s, k), result);
+    }
+
+    #[test]
+    fn test_1945_example_2() {
+        let s = "leetcode".to_string();
+        let k = 2;
+
+        let result = 6;
+
+        assert_eq!(Solution::get_lucky(s, k), result);
+    }
+
+    #[test]
+    fn test_1945_example_3() {
+        let s = "zbax".to_string();
+        let k = 2;
+
+        let result = 8;
+
+        assert_eq!(Solution::get_lucky(s, k), result);
+    }
+}