洛谷1583

1 #include
      
        2 #include
       
         3 using namespace std; 4 const int maxn=1000; 5 int n,x; 6 double a[maxn][maxn]; 7 inline void read(int &k){ 8     k=0; int f=1; char c=getchar(); 9     while(c<'0'||c>'9')c=='-'&&(f=-1),c=getchar();10     while('0'<=c&&c<='9')k=k*10+c-'0',c=getchar();11     k*=f;12 }13 void swap_a(int x,int y){
    for (int i=1;i<=n+1;i++) swap(a[x][i],a[y][i]);}14 bool Gauss(){15     int now=1;16     while(now<=n){17         if (a[now][now]==0){18             for (int i=now+1;i<=n;i++) if(a[i][now]!=0) {swap_a(i,now); break;}19             if (a[now][now]==0) return puts("No Solution"),0;20         } 21         double tmp=a[now][now];22         for (int i=1;i<=n+1;i++) a[now][i]=a[now][i]/tmp;  23         for (int i=1;i<=n;i++){                        24             if (i==now) continue; double tmp=a[i][now];25             for (int j=1;j<=n+1;j++) a[i][j]-=a[now][j]*tmp;26         }27         now++;28     }29     return 1;30 }31 int main(){32     read(n);33     for (int i=1;i<=n;i++)34         for (int j=1;j<=n+1;j++) read(x),a[i][j]=x;35     if (Gauss()) for (int i=1;i<=n;i++) printf("%.2f\n",a[i][n+1]); printf("\n");36     return 0;37 }