View Compilation Error

0_0_15395787_15340.cpp:10:2: error: '_int64' does not name a type
  _int64 sum;
  ^
0_0_15395787_15340.cpp: In function 'void change(int, int, int)':
0_0_15395787_15340.cpp:21:8: error: 'struct COW' has no member named 'sum'
   a[i].sum+=x;
        ^
0_0_15395787_15340.cpp: In function 'int qiu_sum(int)':
0_0_15395787_15340.cpp:30:13: error: 'struct COW' has no member named 'sum'
   sum+=a[i].sum;
             ^
0_0_15395787_15340.cpp: In function 'int main()':
0_0_15395787_15340.cpp:50:3: error: '_int64' was not declared in this scope
   _int64 answer=0;
   ^
0_0_15395787_15340.cpp:56:11: error: expected ';' before 't1'
    _int64 t1=i-qiu_cnt(cow);
           ^
0_0_15395787_15340.cpp:57:7: error: 't1' was not declared in this scope
    if(t1!=0) {
       ^
0_0_15395787_15340.cpp:59:5: error: 'answer' was not declared in this scope
     answer+=t1*cow+t2;
     ^
0_0_15395787_15340.cpp:63:20: error: 'answer' was not declared in this scope
   printf("%I64d\n",answer);
                    ^