foo.cpp:1:1: error: 'include' does not name a type
 include<stdio.h>
 ^
foo.cpp: In function 'int root(int)':
foo.cpp:9:6: error: 'fa' was not declared in this scope
 if (!fa[x]) return x;
      ^
foo.cpp:11:8: error: 'fa' was not declared in this scope
 return fa[x]=root(fa[x]);
        ^
foo.cpp: In function 'void unit(int, int)':
foo.cpp:19:5: error: 'fa' was not declared in this scope
     fa[x]=y;
     ^
foo.cpp: In function 'int main()':
foo.cpp:26:19: error: 'scanf' was not declared in this scope
 scanf("%d%d",&n,&m);
                   ^
foo.cpp:34:27: error: 'N' was not declared in this scope
     if (root(x1)==root(x2+N))
                           ^
foo.cpp:36:29: error: 'printf' was not declared in this scope
         printf("No Answer\n");
                             ^
foo.cpp:40:13: error: 'N' was not declared in this scope
     unit(x1+N,x2+N);
             ^
foo.cpp:46:33: error: 'printf' was not declared in this scope
             printf("No Answer\n");
                                 ^
foo.cpp:51:24: error: 'N' was not declared in this scope
             unit(x1,x2+N);
                        ^
foo.cpp:62:6: error: 'visit' was not declared in this scope
 if (!visit[root(i)]&&(root(i)<=n))
      ^
foo.cpp:69:1: error: 'a' was not declared in this scope
 a[0]=1; l=1;
 ^
foo.cpp:74:5: error: 'c' was not declared in this scope
     c[j]+=a[j]*2;
     ^
foo.cpp:79:14: error: 'c' was not declared in this scope
 while (l>=0&&c[l]==0) --l;
              ^
foo.cpp:82:24: error: 'c' was not declared in this scope
 for (j=0;j<l;++j) a[j]=c[j];
                        ^
foo.cpp:83:8: error: 'c' was not declared in this scope
 memset(c,0,sizeof(c));
        ^
foo.cpp:83:21: error: 'memset' was not declared in this scope
 memset(c,0,sizeof(c));
                     ^
foo.cpp:86:38: error: 'printf' was not declared in this scope
 for (i=l-1;i>=0;--i) printf("%d",a[i]); 
                                      ^
foo.cpp: In function 'int root(int)':
foo.cpp:12:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^