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| using ll = long long;
template<typename T, typename F>
struct disjoint_sparse_table {
int n;
vector<int> log2;
vector<vector<T>> mat;
F func;
disjoint_sparse_table(const vector<T>& arr, const F& f) : n(int(arr.size())), func(f) {
build_log2();
mat.push_back(arr);
int k = log2[n];
for (int i = 1; i <= k; ++i) {
mat.emplace_back(n);
for (int j = 0; j < n - (1 << (i - 1)); ++j) {
mat[i][j] = func(mat[i - 1][j], mat[i - 1][j + (1 << (i - 1))]);
}
}
}
void build_log2() {
log2.resize(n + 5, 0);
log2[1] = 0;
log2[2] = 1;
for (int i = 3; i <= n; ++i) log2[i] = log2[i >> 1] + 1;
}
T query(int l, int r) {
int k = log2[r - l + 1];
return func(mat[k][l], mat[k][r - (1 << k) + 1]);
}
};
|