View Compilation Error

0_0_28654350_29964.cpp: In function 'int query(int, int, int)':
0_0_28654350_29964.cpp:103:45: error: 'struct Block' has no member named 'end'
                 if(b[i].num.find(z) != b[i].end()) ans += b[i].num[z];
                                             ^