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
1 //#include<bits/stdc++.h> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<iostream> 6 #include<queue> 7 #define inc(i,l,r) for(i=l;i<=r;i++) 8 #define dec(i,l,r) for(i=l;i>=r;i--) 9 #define mem(a) memset(a,0,sizeof(a)) 10 #define ll long long 11 #define succ(x) (1<<x) 12 #define NM 100 13 using namespace std; 14 int read(){ 15 int x=0,f=1;char ch=getchar(); 16 while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();} 17 while(isdigit(ch))x=x*10+ch-'0',ch=getchar(); 18 return x*f; 19 } 20 struct matrix{ 21 int a[NM][NM]; 22 }a,b; 23 int i,j,n,k,inf; 24 matrix operator+(const matrix&x,const matrix&y){ 25 matrix s; 26 int i,j; 27 inc(i,1,n) 28 inc(j,1,n) 29 (s.a[i][j]=x.a[i][j]+y.a[i][j])%=inf; 30 return s; 31 } 32 matrix operator*(const matrix&x,const matrix&y){ 33 matrix s; 34 int i,j,k; 35 inc(i,1,n) 36 inc(j,1,n){ 37 s.a[i][j]=0; 38 inc(k,1,n) 39 (s.a[i][j]+=x.a[i][k]*y.a[k][j])%=inf; 40 } 41 return s; 42 } 43 matrix cal(int k){ 44 matrix t=a,s=a; 45 k--; 46 while(k>0){ 47 if(k%2)s=s*t; 48 t=t*t; 49 k/=2; 50 } 51 return s; 52 } 53 matrix sum(int x){ 54 matrix tmp,s,t; 55 if(x==1)return a; 56 t=cal(x/2); 57 tmp=sum(x/2); 58 if(x%2){ 59 s=t*tmp; 60 s=s+tmp; 61 s=s+cal(x); 62 }else{ 63 s=t*tmp; 64 s=s+tmp; 65 } 66 return s; 67 } 68 int main(){ 69 n=read();k=read();inf=read(); 70 inc(i,1,n) 71 inc(j,1,n)a.a[i][j]=read(); 72 b=sum(k); 73 inc(i,1,n){ 74 inc(j,1,n)printf("%d ",b.a[i][j]); 75 printf(" "); 76 } 77 return 0; 78 }