Codeforces Round #420 (Div. 2) E. Okabe and El Psy Kongroo 矩阵快速幂优化dp
2 seconds
256 megabytes
standard input
standard output
Okabe likes to take walks but knows that spies from the Organization could be anywhere; that's why he wants to know how many different walks he can take in his city safely. Okabe's city can be represented as all points (x, y) such that x and y are non-negative. Okabe starts at the origin (point (0, 0)), and needs to reach the point (k, 0). If Okabe is currently at the point (x, y), in one step he can go to (x + 1, y + 1), (x + 1, y), or (x + 1, y - 1).
Additionally, there are n horizontal line segments, the i-th of which goes from x = ai to x = bi inclusive, and is at y = ci. It is guaranteed that a1 = 0, an ≤ k ≤ bn, and ai = bi - 1 for 2 ≤ i ≤ n. The i-th line segment forces Okabe to walk with y-value in the range 0 ≤ y ≤ ci when his x value satisfies ai ≤ x ≤ bi, or else he might be spied on. This also means he is required to be under two line segments when one segment ends and another begins.
Okabe now wants to know how many walks there are from the origin to the point (k, 0) satisfying these conditions, modulo 109 + 7.
The first line of input contains the integers n and k (1 ≤ n ≤ 100, 1 ≤ k ≤ 1018) — the number of segments and the destination x coordinate.
The next n lines contain three space-separated integers ai, bi, and ci (0 ≤ ai < bi ≤ 1018, 0 ≤ ci ≤ 15) — the left and right ends of a segment, and its y coordinate.
It is guaranteed that a1 = 0, an ≤ k ≤ bn, and ai = bi - 1 for 2 ≤ i ≤ n.
Print the number of walks satisfying the conditions, modulo 1000000007 (109 + 7).
1 3
0 3 3
4
2 6
0 3 0
3 10 2
4

The graph above corresponds to sample 1. The possible walks are:

The graph above corresponds to sample 2. There is only one walk for Okabe to reach (3, 0). After this, the possible walks are:
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<queue>
#include<algorithm>
#include<stack>
#include<cstring>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<bitset>
#include<time.h>
using namespace std;
#define LL long long
#define pi (4*atan(1.0))
#define eps 1e-4
#define bug(x) cout<<"bug"<<x<<endl;
const int N=3e5+,M=4e6+,inf=,mod=1e9+;
const LL INF=1e18+,MOD=1e9+; struct Matrix
{
LL a[][];
Matrix()
{
memset(a,,sizeof(a));
}
void init()
{
for(int i=;i<;i++)
for(int j=;j<;j++)
a[i][j]=(i==j);
}
Matrix operator + (const Matrix &B)const
{
Matrix C;
for(int i=;i<;i++)
for(int j=;j<;j++)
C.a[i][j]=(a[i][j]+B.a[i][j])%MOD;
return C;
}
Matrix operator * (const Matrix &B)const
{
Matrix C;
for(int i=;i<;i++)
for(int k=;k<;k++)
for(int j=;j<;j++)
C.a[i][j]=(C.a[i][j]+1LL*a[i][k]*B.a[k][j])%MOD;
return C;
}
Matrix operator ^ (const LL &t)const
{
Matrix A=(*this),res;
res.init();
LL p=t;
while(p)
{
if(p&)res=res*A;
A=A*A;
p>>=;
}
return res;
}
};
map<pair<LL,int> ,LL >dp;
LL a[N],b[N];int c[N];
Matrix Gbase(int n)
{
Matrix a;
a.init();
for(int i=;i<=n;i++)
{
if(i->=)a.a[i-][i]=;
a.a[i][i]=;
if(i+<=n)a.a[i+][i]=;
}
return a;
}
Matrix Gpre(LL x,int n)
{
Matrix a;
a.init();
for(int i=;i<=n;i++)
a.a[][i]=dp[make_pair(x,i)];
return a;
}
int main()
{
int n;
LL k;
scanf("%d%lld",&n,&k);
for(int i=;i<=n;i++)
scanf("%lld%lld%d",&a[i],&b[i],&c[i]);
dp[make_pair(,)]=;
for(int i=;i<=n;i++)
{
Matrix base=Gbase(c[i]);
Matrix pre=Gpre(a[i],c[i]);
LL l=a[i],r=min(b[i],k);
base=base^(r-l);
Matrix ans=pre*base;
for(int j=;j<=c[i];j++)
dp[make_pair(r,j)]=ans.a[][j];
if(b[i]>=k)break;
}
printf("%lld\n",dp[make_pair(k,)]);
return ;
}
Codeforces Round #420 (Div. 2) E. Okabe and El Psy Kongroo 矩阵快速幂优化dp的更多相关文章
- Codeforces Round #420 (Div. 2) E. Okabe and El Psy Kongroo DP+矩阵快速幂加速
E. Okabe and El Psy Kongroo Okabe likes to take walks but knows that spies from the Organization ...
- Codeforces Round #420 (Div. 2) E. Okabe and El Psy Kongroo dp+矩阵快速幂
E. Okabe and El Psy Kongroo Okabe likes to take walks but knows that spies from the Organization c ...
- CF821 E. Okabe and El Psy Kongroo 矩阵快速幂
LINK 题意:给出$n$条平行于x轴的线段,终点$k$坐标$(k <= 10^{18})$,现在可以在线段之间进行移动,但不能超出两条线段的y坐标所夹范围,问到达终点有几种方案. 思路:刚开始 ...
- Codeforces Round #307 (Div. 2) D. GukiZ and Binary Operations (矩阵高速幂)
题目地址:http://codeforces.com/contest/551/problem/D 分析下公式能够知道,相当于每一位上放0或者1使得最后成为0或者1.假设最后是0的话,那么全部相邻位一定 ...
- Codeforces Round #189 (Div. 1) C - Kalila and Dimna in the Logging Industry 斜率优化dp
C - Kalila and Dimna in the Logging Industry 很容易能得到状态转移方程 dp[ i ] = min( dp[ j ] + b[ j ] * a[ i ] ) ...
- Codeforces Round #307 (Div. 2) D. GukiZ and Binary Operations 矩阵快速幂优化dp
D. GukiZ and Binary Operations time limit per test 1 second memory limit per test 256 megabytes inpu ...
- Codeforces Round #420 (Div. 2)
/*************************************************************************************************** ...
- Codeforces Round #420 (Div. 2) A-E
本来打算划划水洗洗睡了,突然听到这次的主人公是冈部伦太郎 石头门(<steins;gate>)主题的比赛,岂有不打之理! 石头门真的很棒啊!人设也好剧情也赞曲子也特别好听. 推荐http: ...
- Codeforces 821E Okabe and El Psy Kongroo(矩阵快速幂)
E. Okabe and El Psy Kongroo time limit per test 2 seconds memory limit per test 256 megabytes input ...
随机推荐
- 前端框架VUE----webpack打包工具的使用
在这里我仅仅的是对webpack做个讲解,webpack这个工具非常强大,解决了我们前端很繁琐的一些工具流程繁琐的事情.如果感兴趣的同学,还是看官网吧. 中文链接地址:https://www.webp ...
- OGG 12.3中支持系统procedure复制的几点说明
如果需要同步系统级别的过程和package,则需要满足以下条件: 要求使用OGG12.3及以后的版本 需要使用oracle db12.2及以后的版本 需要使用集成抽取和集成投递 在DBA_GG_SUP ...
- Java五大框架
2017-6-13 Lifusen 此文章仅代表个人观点,如有问题提出请联系Q:570429601 1.Hibernate (开放源代码的对象关系映射框架) Hibernate是一个开放源代码的对象关 ...
- MyEclipse非正常关闭问题
问题:电脑突然断电,myeclipse非正常关闭,“Package Explorer”非正常显示,出现错误“Could not create the view: An unexpected excep ...
- 关于js的日期处理
1.日期转换(Date)方法一:String变为Date var t = "2015-03-16";var array = t.split("-");var ...
- 安装ubuntu18.04.1
下载ubuntu:https://www.ubuntu.com/download/desktop 在虚拟机创建好ubuntu18.04.1后无法启动(选择的是linux,ubuntu64位),提示:此 ...
- react复习总结(2)--react生命周期和组件通信
这是react项目复习总结第二讲, 第一讲:https://www.cnblogs.com/wuhairui/p/10367620.html 首先我们来学习下react的生命周期(钩子)函数. 什么是 ...
- Yii1使用Gii生成模块实现CURD
Yii里Gii的强大就不用说了,可以快速生成模块的Model.Controller来开发.要使用Gii,首先你需要创建好操作的数据表. 第一步:创建数据表 CREATE TABLE `t_knowle ...
- 上传代码到github的步骤
在你的电脑上装好git 大致流程是: 1.在github上创建项目 2.使用git clone https://github.com/xxxxxxx/xxxxx.git克隆到本地 3.编辑项目 4.g ...
- opencv学习之路(3)、批量读取图片、视频分解、视频合成
一.批量有序读取图片 #include<opencv2/opencv.hpp> using namespace cv; void main() { //批量读取图片(有序) ]; ]; M ...







