<snippet>
    <content><![CDATA[
template<typename T>
class ZkwTree {
    int N = 0;
    T *node;
public:

    ~ZkwTree() { 
        if (!N) return;
        delete[] node; 
    }

    void setval(const ZkwTree& zkwtree) {
        N = zkwtree.N;
        node = new T[(N << 1) + 2]();
    }

    ZkwTree &operator=(const ZkwTree& zkwtree) {
        setval(zkwtree);
        return *this;
    }
    
    ZkwTree(const ZkwTree& zkwtree) {
        setval(zkwtree);
    };

    ZkwTree(int n) {
        for (N = 1; N < n; N <<= 1);
        node = new T[(N << 1) + 2]();
    };

    ZkwTree(std::vector<int>& q) {
        for (N = 1; N < q.size(); N <<= 1);
        node = new T[(N << 1) + 2];
        for (int i = 1; i <= q.size(); i++) {
            node[i + N] = q[i - 1];
        }
        for (int i = N; i; i--) {
            node[i] = std::max(node[i << 1], node[i << 1 | 1]);
        }
    };

    // 下标从0开始
    T query(int left, int right) {
        // 从1开始删除
        left++, right++;
        T res = -2e9;
        left += N - 1, right += N + 1;
        for (; left ^ right ^ 1; left >>= 1, right >>= 1) {
            if (~left & 1) { res = std::max(res, node[left ^ 1]); }
            if (right & 1) { res = std::max(res, node[right ^ 1]); }
        }
        return res;
    }

    void update(int idx, T k) {
        // 从1开始删除 
        idx++;
        node[idx + N] = k;
        for (idx = (idx + N) >> 1; idx > 0; idx >>= 1) {
            node[idx] = std::max(node[idx << 1], node[idx << 1 | 1]);
        }
    }
};
]]></content>
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</snippet>