/in/foo.cc: In function 'int main()':
/in/foo.cc:35:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
             if(queue[tail].s==k)//判断是否到达终点
             ^~
/in/foo.cc:37:14: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
              tail++;
              ^~~~
/in/foo.cc:62:9: warning: unused variable 'i' [-Wunused-variable]
     int i;
         ^