View Compilation Error

0_0_28849794_31089.cpp:8:8: error: 'N' was not declared in this scope
 } tree[N<<2];
        ^
0_0_28849794_31089.cpp:10:12: error: 'N' was not declared in this scope
 int sorted[N];
            ^
0_0_28849794_31089.cpp:11:13: error: 'N' was not declared in this scope
 int val[20][N],toLeft[20][N];
             ^
0_0_28849794_31089.cpp:11:27: error: 'N' was not declared in this scope
 int val[20][N],toLeft[20][N];
                           ^