poj 3233

NOIP会考矩乘？看了一下blog，在代码上改得比较易懂一点。。

这道2次二分作为矩乘的开始

//#include<bits/stdc++.h>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<queue>
#define inc(i,l,r) for(i=l;i<=r;i++)
#define dec(i,l,r) for(i=l;i>=r;i--)
#define mem(a) memset(a,0,sizeof(a))
#define ll long long
#define succ(x) (1<<x)
#define NM 100
using namespace std;
int read(){
    int 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;
}
struct matrix{
    int a[NM][NM];
}a,b;
int i,j,n,k,inf;
matrix operator+(const matrix&x,const matrix&y){
    matrix s;
    int i,j;
    inc(i,1,n)
    inc(j,1,n)
    (s.a[i][j]=x.a[i][j]+y.a[i][j])%=inf;
    return s;
}
matrix operator*(const matrix&x,const matrix&y){
    matrix s;
    int i,j,k;
    inc(i,1,n)
    inc(j,1,n){
        s.a[i][j]=0;
        inc(k,1,n)
        (s.a[i][j]+=x.a[i][k]*y.a[k][j])%=inf;
    }
    return s;
}
matrix cal(int k){
    matrix t=a,s=a;
    k--;
    while(k>0){
        if(k%2)s=s*t;
        t=t*t;
        k/=2;
    }
    return s;
}
matrix sum(int x){
    matrix tmp,s,t;
    if(x==1)return a;
    t=cal(x/2);
    tmp=sum(x/2);
    if(x%2){
        s=t*tmp;
        s=s+tmp;
        s=s+cal(x);
    }else{
        s=t*tmp;
        s=s+tmp;
    }
    return s;
}
int main(){
    n=read();k=read();inf=read();
    inc(i,1,n)
    inc(j,1,n)a.a[i][j]=read();
    b=sum(k);
    inc(i,1,n){
        inc(j,1,n)printf("%d ",b.a[i][j]);
        printf("
");
    }
    return 0;
}