一个简单的线段树 #include <bits/stdc++.h> #define il inline #define double long double using namespace std; using ll = long long; using ull = unsigned long long; using int128 = __int128_t; const ll N = 5e5 + 5, mod = 1e9+7, inf = 2e18; const double eps = 1e-9; double PI = 3.1415926; int a[N],tree[N<...