Create 880. Decoded String at Index

C++/880. Decoded String at Index

@@ -0,0 +1,31 @@
+class Solution {
+public:
+ std::string decodeAtIndex(std::string inputString, int k) {
+ long long decodedLength = 0; // Total length of the decoded string
+ for (auto character : inputString) {
+ if (isdigit(character)) {
+ // If the character is a digit, update the decoded length accordingly
+ decodedLength *= character - '0';
+ } else {
+ // If the character is a letter, increment the decoded length
+ decodedLength++;
+ }
+ }
+
+ // Traverse the input string in reverse to decode and find the kth character
+ for (int i = inputString.size() - 1; i >= 0; i--) {
+ if (isdigit(inputString[i])) {
+ // If the character is a digit, adjust the length and k accordingly
+ decodedLength /= (inputString[i] - '0');
+ k = k % decodedLength;
+ } else {
+ // If the character is a letter, check if it's the kth character
+ if (k == 0 || decodedLength == k)
+ return string("") + inputString[i]; // Return the kth character as a string
+ decodedLength--;
+ }
+ }
+
+ return ""; // Return an empty string if no character is found
+ }
+};