View Compilation Error

0_0_26521504_4329.cpp:5:11: error: size of array 'a' is not an integral constant-expression
 int a[maxn],b[maxn];
           ^
0_0_26521504_4329.cpp:5:19: error: size of array 'b' is not an integral constant-expression
 int a[maxn],b[maxn];
                   ^
0_0_26521504_4329.cpp:6:22: error: size of array 'edge' is not an integral constant-expression
 vector<int> edge[maxn];
                      ^
0_0_26521504_4329.cpp: In function 'void dfs(int, int)':
0_0_26521504_4329.cpp:15:18: error: 'k' was not declared in this scope
         if(a[v]>=k&&n-a[v]>=k)
                  ^
0_0_26521504_4329.cpp:15:21: error: 'n' was not declared in this scope
         if(a[v]>=k&&n-a[v]>=k)
                     ^