View Compilation Error

0_0_26678670_6334.cpp:6:8: error: 'maxn' was not declared in this scope
 } tree[maxn];
        ^
0_0_26678670_6334.cpp:8:12: error: 'maxn' was not declared in this scope
 int stack1[maxn];
            ^
0_0_26678670_6334.cpp: In function 'void build(int)':
0_0_26678670_6334.cpp:11:5: error: 'stack1' was not declared in this scope
     stack1[++tot] = 1;
     ^
0_0_26678670_6334.cpp:12:5: error: 'tree' was not declared in this scope
     tree[1].pos = s[1].pos;
     ^
0_0_26678670_6334.cpp:12:19: error: 's' was not declared in this scope
     tree[1].pos = s[1].pos;
                   ^