Create TheRecusriveStackProblem.cpp

Author: rachitiitr

Famous-Coding-Interview-Problems/TheRecusriveStackProblem.cpp

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+class Solution {
+public:
+    vector<int> en;
+    int go(int lo, int hi) {
+        if(lo+1 == hi) return 1;
+        int mid = en[lo];
+        if(mid == hi) return 2*go(lo+1, hi-1);
+        return go(lo, mid) + go(mid+1, hi);
+    }
+    
+    //calculates the score of string S
+    //This is solution of my YouTube video "The Recursive Stack Problem on Strings"
+    int scoreOfParentheses(string &S) {
+        int i, n = (int)S.size();
+        n = max(n, 1);
+        en.resize(n, 0);
+        stack<int> s;
+        for(i=0; i<n; i++){
+            if(S[i] == ')'){
+                int t = s.top();
+                en[t] = i;
+                s.pop();
+            }
+            else s.push(i);
+        }
+        return go(0, n-1);
+    }
+};