/in/foo.cc:9:1: error: expected ',' or ';' before 'int'
 int f[N][N];//f[i][j]为第i到j这个区间中的最小合并代价
 ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:25:13: error: 'f' was not declared in this scope
             f[i][j]=0x3f3f3f3f;//初始化为最大值
             ^
/in/foo.cc:33:11: error: 'f' was not declared in this scope
     cout<<f[1][n];
           ^