/in/foo.cc: In function 'int dfs(int, int, int)':
/in/foo.cc:22:18: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
   for(int i = X[i];i<=m-h-Y[x];i+=X[i])ret = min(ret,dfs(x+1,h-Y[x]+i,i/X[i]+step));
                  ^
/in/foo.cc:25:18: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
   for(int i = X[i];i<=m-h-Y[x];i+=X[i])ret = min(ret,dfs(x+1,h-Y[x]+i,i/X[i]+step));
                  ^