View Compilation Error

0_0_36480517_1692.cpp:22:10: error: 'a' does not name a type
 int a[N];a
          ^
0_0_36480517_1692.cpp: In function 'void init()':
0_0_36480517_1692.cpp:29:37: error: 'w' was not declared in this scope
  for (int i=1;i<=n;i++) a[i]=read(),w[i]=0,V[i].clear();
                                     ^
0_0_36480517_1692.cpp:34:3: error: 'w' was not declared in this scope
   w[x]+=z;
   ^
0_0_36480517_1692.cpp: In function 'void add(ll, ll, ll)':
0_0_36480517_1692.cpp:53:2: error: 'w' was not declared in this scope
  w[u]+=t;
  ^
0_0_36480517_1692.cpp: In function 'int solve()':
0_0_36480517_1692.cpp:70:16: error: 'w' was not declared in this scope
   if (abs(a[i]^w[i])&1) return puts("NO");
                ^
0_0_36480517_1692.cpp:72:15: error: 'w' was not declared in this scope
   wsum[d[i]]+=w[i];
               ^
0_0_36480517_1692.cpp:86:8: error: 'w' was not declared in this scope
    if (w[t]>0) add(k,t,w[t]/2),add(k,t,w[t]/2);
        ^