BZOJ-3231 [SDOI2008]递归数列

转成矩阵连乘后，矩阵快速幂加速解决。

一开始没把需要longlong的变量补全。。而且没初始化2333

#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cctype>
#include <cmath>
#include <algorithm>
#include <iostream>
#define rep(i, l, r) for(int i=l; i<=r; i++)
#define clr(x, c) memset(x, c, sizeof(x))
#define maxn 20
#define ll long long
#define l(x) x*2
#define r(x) x*2+1
using namespace std;
inline ll read()
{
	ll x=0, f=1; char ch=getchar();
	while (!isdigit(ch)) {if (ch=='-') f=-1; ch=getchar();}
	while (isdigit(ch)) x=x*10+ch-'0', ch=getchar();
	return x*f;
}
int n;
ll q;
ll m[maxn][maxn], m2[maxn][maxn], b[maxn], c[maxn], a[maxn], a2[maxn];

ll Query(ll k)
{
	if (k<=n) {ll now=0; rep(i, 1, k) now+=b[i]; return now;} else k-=n;
	clr(m, 0);
	rep(i, 1, n) m[n][n+1-i]=m[n+1][n+1-i]=c[i];
	rep(i, 1, n-1) m[i][i+1]=1; m[n+1][n+1]=1;
	rep(i, 1, n+1) a[i]=b[i];
	while (k)
	{
		if (k&1)
		{
			clr(a2, 0);
			rep(i, 1, n+1) rep(j, 1, n+1) a2[i]=(a2[i]+a[j]*m[i][j])%q;
			rep(i, 1, n+1) a[i]=a2[i];
		}
		clr(m2, 0);
		rep(i, 1, n+1) rep(j, 1, n+1) rep(o, 1, n+1) m2[i][j]=(m2[i][j]+m[i][o]*m[o][j])%q;
		rep(i, 1, n+1) rep(j, 1, n+1) m[i][j]=m2[i][j];
		k=k>>1;
	}
	return a[n+1];
}

int main()
{
	n=read();
	rep(i, 1, n) b[i]=read(), b[n+1]+=b[i];
	rep(i, 1, n) c[i]=read();
	ll x=read(), y=read(); q=read();
	rep(i, 1, n) b[i]%=q, c[i]%=q;
	printf("%lld", (Query(y)-Query(x-1)+2*q)%q);
	return 0;
}