View Compilation Error

0_0_34544245_30293.cpp:7:7: error: 'N' was not declared in this scope
 int a[N], cnt[MAXV + 1];
       ^
0_0_34544245_30293.cpp: In function 'int main()':
0_0_34544245_30293.cpp:17:26: error: 'a' was not declared in this scope
             scanf("%d", &a[i]);
                          ^
0_0_34544245_30293.cpp:22:25: error: 'a' was not declared in this scope
                 cnt[abs(a[i] - a[j])]++;
                         ^