/in/foo.cc: In function 'void DFS1(int, int, ull, int, int)':
/in/foo.cc:98:10: warning: unused variable 't' [-Wunused-variable]
  int i,y,t;
          ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:212:26: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
       while(c[i]=getchar())
                          ^
/in/foo.cc:222:24: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
     while(s[i]=getchar())
                        ^