{

int n;

T val;

vector<T> vec;

function<T(T, T)> comb;

segTree(int nt, T val, function<T(T, T)> func) : n(nt), val(val), comb(func)

{

//combinator function is used to define the use case(RANGE_SUM,RANGE_MIN,RANGE_MAX)

//val initializes the array accordingly

vec.resize(2 * n + 1, val);

build();

}

void build()

{

for (int i = 1; i <= n; i++)

{

vec[i + n] = arr[i];

}

for (int i = n; i > 1; --i)

{

vec[i] = comb(vec[i << 1], vec[i << 1 | 1]);

}

}

void update(int p, T value)

{ // set value at position p

for (vec[p += n] = value; p > 1; p >>= 1)

{

vec[p >> 1] = comb(vec[p], vec[p ^ 1]);

}

}

T query(int l, int r)

{ // sum on interval [l, r)

T res = val;

for (l += n, r += n; l < r; l >>= 1, r >>= 1)

{

if (l & 1)

res = comb(res, vec[l++]);

if (r & 1)

res = comb(res, vec[--r]);

}

return res;

}