View Compilation Error

0_0_17475394_25873.cpp: In function 'int main()':
0_0_17475394_25873.cpp:45:16: error: 'sum' was not declared in this scope
             if(sum%2==1)
                ^
0_0_17475394_25873.cpp:51:25: error: 'struct node' has no member named 'x'
         printf("%d\n",w.x);//打印最后一块石头的坐标就是所求//的最远距离
                         ^