View Compilation Error

0_0_33888727_1491.cpp:5:7: error: 'maxn' was not declared in this scope
 int a[maxn] , sum[maxn];
       ^
0_0_33888727_1491.cpp:5:19: error: 'maxn' was not declared in this scope
 int a[maxn] , sum[maxn];
                   ^
0_0_33888727_1491.cpp: In function 'bool solve(int)':
0_0_33888727_1491.cpp:18:16: error: 'sum' was not declared in this scope
         all += sum[mo];
                ^
0_0_33888727_1491.cpp:21:48: error: 'a' was not declared in this scope
     for(int i = mo + 1 ; i <= n ; i ++) p.push(a[i]);
                                                ^
0_0_33888727_1491.cpp: In function 'int main()':
0_0_33888727_1491.cpp:50:27: error: 'a' was not declared in this scope
             scanf("%d" , &a[i]);
                           ^
0_0_33888727_1491.cpp:52:14: error: 'a' was not declared in this scope
         sort(a +1 , a + 1 + n);
              ^
0_0_33888727_1491.cpp:53:9: error: 'sum' was not declared in this scope
         sum[0]  = 0;
         ^