New Problem Solution - "1844. Replace All Digits with Characters"

README.md

@@ -9,6 +9,7 @@ LeetCode
 
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
+|1844|[Replace All Digits with Characters](https://leetcode.com/problems/replace-all-digits-with-characters/) | [C++](./algorithms/cpp/replaceAllDigitsWithCharacters/ReplaceAllDigitsWithCharacters.cpp)|Easy|
 |1840|[Maximum Building Height](https://leetcode.com/problems/maximum-building-height/) | [C++](./algorithms/cpp/maximumBuildingHeight/MaximumBuildingHeight.cpp)|Hard|
 |1839|[Longest Substring Of All Vowels in Order](https://leetcode.com/problems/longest-substring-of-all-vowels-in-order/) | [C++](./algorithms/cpp/longestSubstringOfAllVowelsInOrder/LongestSubstringOfAllVowelsInOrder.cpp)|Medium|
 |1838|[Frequency of the Most Frequent Element](https://leetcode.com/problems/frequency-of-the-most-frequent-element/) | [C++](./algorithms/cpp/frequencyOfTheMostFrequentElement/FrequencyOfTheMostFrequentElement.cpp)|Medium|

algorithms/cpp/replaceAllDigitsWithCharacters/ReplaceAllDigitsWithCharacters.cpp

@@ -0,0 +1,54 @@
+// Source : https://leetcode.com/problems/replace-all-digits-with-characters/
+// Author : Hao Chen
+// Date   : 2021-05-03
+
+/***************************************************************************************************** 
+ *
+ * You are given a 0-indexed string s that has lowercase English letters in its even indices and 
+ * digits in its odd indices.
+ * 
+ * There is a function shift(c, x), where c is a character and x is a digit, that returns the x^th 
+ * character after c.
+ * 
+ * 	For example, shift('a', 5) = 'f' and shift('x', 0) = 'x'.
+ * 
+ * For every odd index i, you want to replace the digit s[i] with shift(s[i-1], s[i]).
+ * 
+ * Return s after replacing all digits. It is guaranteed that shift(s[i-1], s[i]) will never exceed 
+ * 'z'.
+ * 
+ * Example 1:
+ * 
+ * Input: s = "a1c1e1"
+ * Output: "abcdef"
+ * Explanation: The digits are replaced as follows:
+ * - s[1] -> shift('a',1) = 'b'
+ * - s[3] -> shift('c',1) = 'd'
+ * - s[5] -> shift('e',1) = 'f'
+ * 
+ * Example 2:
+ * 
+ * Input: s = "a1b2c3d4e"
+ * Output: "abbdcfdhe"
+ * Explanation: The digits are replaced as follows:
+ * - s[1] -> shift('a',1) = 'b'
+ * - s[3] -> shift('b',2) = 'd'
+ * - s[5] -> shift('c',3) = 'f'
+ * - s[7] -> shift('d',4) = 'h'
+ * 
+ * Constraints:
+ * 
+ * 	1 <= s.length <= 100
+ * 	s consists only of lowercase English letters and digits.
+ * 	shift(s[i-1], s[i]) <= 'z' for all odd indices i.
+ ******************************************************************************************************/
+
+class Solution {
+public:
+    string replaceDigits(string s) {
+        for(int i=0; i<s.size(); i+=2) {
+            s[i+1] = s[i] + s[i+1] - '0';
+        }
+        return  s;
+    }
+};