View Compilation Error

0_0_20806231_21559.cpp:2:1: error: '_int64' does not name a type
 _int64 jiechen(int i)
 ^
0_0_20806231_21559.cpp: In function 'int main()':
0_0_20806231_21559.cpp:13:2: error: '_int64' was not declared in this scope
  _int64 score;
  ^
0_0_20806231_21559.cpp:14:10: error: expected ';' before 's'
  _int64  s[1000]={0};
          ^
0_0_20806231_21559.cpp:15:2: error: 's' was not declared in this scope
  s[1]=0;
  ^
0_0_20806231_21559.cpp:26:4: error: 'score' was not declared in this scope
    score=jiechen(m);
    ^
0_0_20806231_21559.cpp:26:19: error: 'jiechen' was not declared in this scope
    score=jiechen(m);
                   ^