Data Structures

Displayed Nodes in a Tree View

Difficulty

Asked at Jane Street

Theory: Data Structures You Implement, Not Import

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Available in Python and C++. You are solving it in C++. Switch to Python

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Language:

Python 3.12 C++23

run_ops

#include <string_view>
#include <utility>
#include <vector>

class TreeView {
public:
    // ...
    // ...
    explicit TreeView(const std::vector<int>& parents) {
        // ...
        (void)parents;
    }

    // ...
    void select(int v) {
        // ...
        (void)v;
    }

    // ...
    void deselect(int v) {
        // ...
        (void)v;
    }

    // ...
    long long count() const {
        // ...
        return -1;
    }

    // ...
    // ...
    // ...
    std::vector<int> displayed() const {
        // ...
        return {-1};
    }
};

// ...
// ...
struct Op {
    std::string_view kind;
    int node = 0;
};

// ...
// ...
// ...
std::pair<std::vector<std::vector<int>>, std::vector<long long>> run_ops(const std::vector<int>& parents,
                                                                         const std::vector<Op>& ops) {
    TreeView view(parents);
    std::pair<std::vector<std::vector<int>>, std::vector<long long>> out;
    for (const Op& op : ops) {
        if (op.kind == "select") {
            view.select(op.node);
        } else if (op.kind == "deselect") {
            view.deselect(op.node);
        } else if (op.kind == "displayed") {
            out.first.push_back(view.displayed());
        } else {
            out.second.push_back(view.count());
        }
    }
    return out;
}

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