Merge pull request #3122 from nkawaller/decode-string

Create: 0394-decode-string.cpp

Author: sujal-goswami

cpp/0394-decode-string.cpp

@@ -0,0 +1,40 @@
+class Solution {
+public:
+    string decodeString(string s) {
+        stack<string> stack;
+        string result;
+
+        for (int i = 0; i < s.length(); i++) {
+            if (s[i] != ']') {
+                stack.push(string(1, s[i]));
+            } else {
+                string substr;
+                while (!stack.empty() && stack.top() != "[") {
+                    substr = stack.top() + substr;
+                    stack.pop();
+                }
+                stack.pop();
+
+                string k;
+                while (!stack.empty() && isdigit(stack.top()[0])) {
+                    k = stack.top() + k;
+                    stack.pop();
+                }
+                int kInt = stoi(k);
+
+                string temp;
+                for (int j = 0; j < kInt; j++) {
+                    temp += substr;
+                }
+                stack.push(temp);
+            }
+        }
+
+        while (!stack.empty()) {
+            result = stack.top() + result;
+            stack.pop();
+        }
+
+        return result;
+    }
+};