题目链接：最大异或对

#include <iostream>
#include <algorithm>using namespace std;const int N = 100010, M = 31 * N;int a[N];
int son[M][2], idx;void insert(int x)
{int p = 0;for(int i = 30; i >= 0; i --){int u = x >> i & 1;if(!son[p][u]) son[p][u] = ++ idx;p = son[p][u];}
}int query(int x)
{int p = 0, res = 0;for(int i = 30; i >= 0; i --){int u = x >> i & 1;if(son[p][!u]){p = son[p][!u];res = res * 2 + !u;}else{p = son[p][u];res = res * 2 + u;}}return res;
}int main()
{int n;cin >> n;for(int i = 0; i < n; i ++) cin >> a[i];int res = 0;for(int i = 0; i < n; i++){insert(a[i]);int t = query(a[i]);res = max(res, a[i] ^ t);}cout << res << endl;return 0;
}