5

2 9 5 7 0

14

 1 #include <iostream>

 2 using namespace std;

 3 int n;

 4 const int N = 1e5 + 5;

 5 int a[N];

 6 int son[N * 35][3], cnt[N * 35];

 7 int idx;

 8

 9 void insert(int x) {

10     int p = 0;

11

12     for (int i = 30; i >= 0; i--) {

13         int u = (x >> i) & 1;

14

15         if (!son[p][u])

16             son[p][u] = ++idx;

17

18         p = son[p][u];

19     }

20

21     cnt[p] = x;

22 }

23

24 int query(int x) {

25     int p = 0;

26     int ans = 0;

27

28     for (int i = 30; i >= 0; i--) {

29         int u = (x >> i) & 1;

30

31         if (son[p][u ^ 1]) {

32             ans += 1 << i;

33             p = son[p][u ^ 1];

34         } else

35             p = son[p][u];

36     }

37

38     return ans;

39 }

40

41 int main() {

42     scanf("%d", &n);

43     int res = 0;

44

45     for (int i = 1; i <= n; i++)

46         scanf("%d", &a[i]), insert(a[i]);

47

48     for (int i = 1; i <= n; i++) {

49         int t = query(a[i]);

50

51         if (t > res)

52             res = t;

53     }

54

55     cout << res << '\n';

56     return 0;

57 }