hdu3359 Kind of a Blur

因为变化出来的是平均数，那么就可以对每一个变化出来的列方程，直接高斯消元就行了。

 #include<bits/stdc++.h>
 #define N 100005
 #define LL long long
 #define inf 0x3f3f3f3f
 #define ls c[x][0]
 #define rs c[x][1]
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 const int maxn=;
 const double eps=1e-;
 double a[maxn][maxn];
 double ave[][];
 double b[maxn];
 void guass(int n, int m)
 {
     int equ=n*m,var=n*m;
     for (int row=,col=; row<=equ && col<=var; row++,col++)
     {
         int maxr=row;
         for (int i=row; i<=equ; i++)
             if (fabs(a[i][col])-fabs(a[maxr][col])>eps)
                 maxr=i;
         if (fabs(a[maxr][col])<eps)
         {
             row--; continue;
         }
         if (maxr!=row)
             for (int j=col; j<=var+; j++)
                 swap(a[maxr][j],a[row][j]);
         for (int i=row+; i<=equ; i++)
             if (fabs(a[i][col])>eps)
             {
                 double s=a[i][col]/a[row][col];
                 for (int j=col; j<=var+; j++)
                     a[i][j]-=a[row][j]*s;
             }
     }
     for (int i=equ; i>=; i--)
     {
         double tmp=a[i][var+];
         for (int j=i+; j<=var; j++)
             tmp-=a[i][j]*b[j];
         b[i]=tmp/a[i][i];
     }
 }
 int main()
 {
     int n,m,d; int first=;
     while (~scanf("%d%d%d",&m,&n,&d))
     {
         memset(a,,sizeof(a));
         if (n+m+d==) break;
         for (int i=; i<=n; i++)
             for (int j=; j<=m; j++)
                 scanf("%lf",&ave[i][j]);
         for (int k=; k<=n*m; k++)
         {
             int x=(k-)/m+,y=k%m; if (!y) y=m;
             double num=;
             for (int i=; i<=n; i++)
                 for (int j=; j<=m; j++)
                     if (abs(i-x)+abs(j-y)<=d)
                         a[k][(i-)*m+j]=,num++;
             a[k][n*m+]=num*ave[x][y];
         }
         guass(n,m);
         if (first) first=; else cout<<endl;
         for (int i=; i<=n*m; i++)
         {
             printf("%8.2lf",b[i]);
             if (i%m==) printf("\n");
         }
     }
     return ;
 }