CODEWITHSUNDEEP
c++stringistringstream
Code_Complete
Code_Complete

Reputation: 115

Best way to achieve this sort of workflow in C++?

I am doing this problem: https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/

My approach is to assign serialized string to a stream like "1,#,2,#,#". And then read a character from stream. If it is a '#', return. Else, visit left and right child.

class Solution {
    stringstream pre; int char_count = 0;
public:
    bool visit() {
        if (char_count >= pre.str().size()) return 0;
        char key; char comma;
        while (char_count < pre.str().size() && pre.peek() != ',') {
            pre >> key;
            char_count++;
        }
        if (pre.peek() == ',') {
            pre >> comma;
            char_count++;
        }
        if (key == '#') return 1;

        return visit() && visit();
    }

    bool isValidSerialization(string preorder) {
        pre << preorder;
        cout << "preorder: " << preorder << endl;
        if (!visit()) return 0;
        if (pre.str().size() > char_count) return 0;
        return 1;
    }
};

int main() {
    Solution q;
    cout << q.isValidSerialization("1,#,#");
}

Earlier, I was checking for 

if (!pre.str().size())

because I wrongly expected stream to delete the extracted characters. Now I am maintaining char_count but the code is no longer elegant. Is there any way to simplify this in C++.

Upvotes: 0

Views: 67

Answers (1)

Fantastic Mr Fox
Fantastic Mr Fox

Reputation: 33864

Have a look here. There is no overload for the operator>>(char), it is likely being implicitly cast to something else. This is the expected behaviour of the code you have written.

Upvotes: 1

Related Questions