【bzoj3120】Line dp+矩阵乘法

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矩乘优化即可

是我的矩乘太丑了嘛？为什么跑的这么慢？

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<iostream>
#include<algorithm>
#define mod 1000000007

using namespace std;

struct yts1
{
	int x,y,z;
}q[410];

struct yts
{
	int x,y;
	int a[210][210];
}a,b,c,ans;

long long m;
int CC[10][10];
int n,P,Q,size;

void mul(yts &a,yts &b,yts &c)
{
	memset(ans.a,0,sizeof(ans.a));
	for (int i=1;i<=a.x;i++)
	  for (int k=1;k<=a.y;k++)
	    if (a.a[i][k])
		  for (int j=1;j<=b.y;j++)
		    if (b.a[k][j])
		      ans.a[i][j]=(ans.a[i][j]+(long long)a.a[i][k]*b.a[k][j]%mod)%mod;
	c.x=a.x;c.y=b.y;
	for (int i=1;i<=c.x;i++)
	  for (int j=1;j<=c.y;j++)
	    c.a[i][j]=ans.a[i][j];
}

void power(yts &a,long long y)
{
	c.x=size;c.y=size;
	memset(c.a,0,sizeof(c.a));
	for (int i=1;i<=size;i++) c.a[i][i]=1;
	while (y)
	{
		if (y&1) mul(c,a,c);
		mul(a,a,a);
		y>>=1;
	}
}

int main()
{
	scanf("%d%lld%d%d",&n,&m,&P,&Q);
	CC[0][0]=1;
	for (int i=1;i<=n;i++)
	{
		CC[i][0]=1;
		for (int j=1;j<=i;j++) CC[i][j]=(CC[i-1][j]+CC[i-1][j-1])%mod;
	}	
	memset(b.a,0,sizeof(b.a));
	for (int i=0;i<=Q;i++)
	  for (int j=0;j<=n;j++)
	    for (int k=0;k<=n;k++)
	      if (j+k<=n)
	      {
	      	int z=n-j-k;
	      	if (P==1 && (z || k)) continue;
	      	if (P==2 && z) continue;
	      	q[++size]=(yts1){i,j,k};
	      	if (i==0 && j==n && k==0) b.a[1][size]=1;
	      }
	b.x=1;b.y=size;a.x=size;a.y=size;
	for (int i=1;i<=size;i++)
	  for (int j=1;j<=size;j++)
	  {
	  	int x=q[i].x,A=q[i].y,B=q[i].z,C=n-A-B;
	  	int xx=q[j].x,aa=q[j].y,bb=q[j].z,cc=n-aa-bb;
	  	if (xx<x || xx>x+1) continue;
	  	if (xx==x+1)
	  	{
	  		if (aa || A!=bb || B!=cc || C) continue;
	  		a.a[i][j]=1;
	  	}
	  	else
	  	{
	  		if (bb>A || cc>B) continue;
	  		a.a[i][j]=CC[A][bb]*CC[B][cc]%mod;
	  		if (!aa && A==bb && B==cc && !C) a.a[i][j]--;
	  	}
	  }
	power(a,m);
	mul(b,c,b);
	int ans=0;
	for (int i=1;i<=size;i++) ans=(ans+b.a[1][i])%mod;
	printf("%d\n",ans);
	return 0;
}

【bzoj3120】Line dp+矩阵乘法

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原文地址：http://blog.csdn.net/u012288458/article/details/51356246