how can i change merge and build function (lazy segment tree)

[the-hyp0cr1t3]

how can i change merge and build function (lazy segment tree)

[the-hyp0cr1t3]

Not sure if I understood your query correctly, but you have to modify SegmentTree::fun to perform whatever operation you need to.

T fun(T a, T b) { return std::min(a, b); }

[MdNihal05]

Thanks for considering this and Sorry that I was not clear
I know how to use this template as i learned classic segment trees

I provided this code as reference
Iam asking about the code in your repository
As I am learning lazy segment trees
https://github.com/the-hyp0cr1t3/CC/blob/master/%E6%9C%AB%20Snippets/Segment%20trees/Recursive%20%2B%20Range%20updates%20(lazy%20prop).cpp

Is there any generic function that I can write instead of changing every where as I did in above code

Or how should I do that ( where should I change for mins,max,sum,or gcd,LCM etc for any cumulative functions)

You can explain by taking any example
The default templete is for min i think?

I hope I am clear this time
Thanks in advance!

[the-hyp0cr1t3]

Oh I see, thanks for clarifying. You'll have to make changes in the Node struct.

For example, for range max query and range sum update, it would look something like this:

const int64_t inf = 2e18;

struct Node {
    using V = int64_t;
    using L = int64_t;

    bool pending{false};
    V val; L lazy{};
    Node(V val = -inf): val(val) {}               // default value
    Node(const Node& l, const Node& r)            // merge two nodes
        : val(std::max(l.val, r.val)) {}
    void apply_lazy(int len) { val += lazy; }     // update node
    operator V() const { return val; }
};

Similarly, range gcd query and range assignment updates would look like:

struct Node {
    using V = int64_t;
    using L = struct Lazy {
        V lzy;
        Lazy(V lzy = 0): lzy(lzy) {}            // default value
        operator V() const { return lzy; }
        void operator+=(const Lazy& rhs) { lzy = rhs.lzy; }    // combine with other lazy
    };

    bool pending{false};
    V val; L lazy{};
    Node(V val = 0): val(val) {}                // default values
    Node(const Node& l, const Node& r)          // merge two nodes
        : val(std::gcd(l.val, r.val)) {}
    void apply_lazy(int len) { val = lazy; }    // update node
    operator V() const { return val; }
};

[MdNihal05]

hey Thanks !