/in/foo.cc: In function 'bool spfa()':
/in/foo.cc:36:47: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
     for(int i=s;i<=t;++i) dis[i]=0,vis[i]=d[i]=0;
                                           ~~~~^~
/in/foo.cc: In function 'int dfs(int, int)':
/in/foo.cc:64:34: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
         if(flow=dfs(y,min(res,v)))
                                  ^
/in/foo.cc: In function 'void dinic()':
/in/foo.cc:88:29: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
         while(flow=dfs(s,inf))
                             ^