hdu1754 I Hate It

无序序列，两种操作：单点修改，区间查询最大值～

void query_max(int a, int b) {
  Node *left, *mid, *right, *o;
  split(ss.root, a, left, o);
  split(o, b-a+1, mid, right);
  printf ( "%d\n", mid->ma );
  ss.root = merge(merge(left, mid), right);
}
void update(int a, int b) {
  Node *left, *mid, *right, *o;
  split(ss.root, a, left, o);
  split(o, 1, mid, right);
  mid->v = b;
  mid->ma = b;
  mid->lazy = b;
  ss.root = merge(merge(left, mid), right);
}