【开源社区openEuler实践】D2. Reverse Card (Hard Version)

题目

题解：

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define lson p << 1
#define rson p << 1 | 1
#define ll long long
#define pii pair<int, int>
#define ld long double
const int maxn = 1e6 + 5, inf = 1e18, maxm = 4e4 + 5, base = 37;
const int N = 2e6;
const int mod = 1e9 + 7;
// const int mod = 998244353;
// const __int128 mod = 212370440130137957LL;
int n, m;

int qpow(int a, int b){
	int res = 1;
	while(b){
		if(b & 1) res = res * a % mod;
		a = a * a % mod;
		b >>= 1;
	}
	return re