View Compilation Error

0_0_28440507_20561.cpp: In function 'double solve(int, int)':
0_0_28440507_20561.cpp:29:56: error: cannot convert 'P' to 'int' for argument '1' to 'double dis(int, int)'
  if(left + 1 == right) return dis(pos[left], pos[right]);
                                                        ^