link:http://codeforces.com/problemset/problem/336/C 从大到小枚举,如果对应的二进制位不等于0,就加进来,最后的sum如果%2^k==0那么就是合法的. #include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> #include <cmath> #include <cctype> #inclu…