View Compilation Error

0_0_20333808_6635.cpp:139:16: error: 'MAXN' was not declared in this scope
 vector <int> G[MAXN];
                ^
0_0_20333808_6635.cpp: In function 'int main()':
0_0_20333808_6635.cpp:149:13: error: 'G' was not declared in this scope
             G[i].clear();
             ^
0_0_20333808_6635.cpp:165:21: error: 'G' was not declared in this scope
                     G[a[i].ID].push_back(a[j].ID);
                     ^
0_0_20333808_6635.cpp:171:16: error: 'G' was not declared in this scope
             if(G[a[i].ID].size()<a[i].cnt){
                ^
0_0_20333808_6635.cpp:183:27: error: 'G' was not declared in this scope
             for(int j=0;j<G[i].size();j++){
                           ^