View Compilation Error

0_0_22825923_10963.cpp:5:1: error: '_int64' does not name a type
 _int64 dp[maxn][maxn];
 ^
0_0_22825923_10963.cpp: In function 'int main()':
0_0_22825923_10963.cpp:13:10: error: 'dp' was not declared in this scope
   memset(dp,0,sizeof(dp));
          ^
0_0_22825923_10963.cpp:34:3: error: '_int64' was not declared in this scope
   _int64 sum = 0;
   ^
0_0_22825923_10963.cpp:37:4: error: 'sum' was not declared in this scope
    sum+=dp[i][k];
    ^
0_0_22825923_10963.cpp:39:20: error: 'sum' was not declared in this scope
   printf("%I64d\n",sum);
                    ^