888G - Xor-MST

#include<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<cstdlib>
#include<climits>
#include<stack>
#include<vector>
#include<queue>
#include<set>
#include<bitset>
#include<map>
//#include<regex>
#include<cstdio>
#include <iomanip>
#pragma GCC optimize(2)
#define up(i,a,b)  for(int i=a;i<b;i++)
#define dw(i,a,b)  for(int i=a;i>b;i--)
#define upd(i,a,b) for(int i=a;i<=b;i++)
#define dwd(i,a,b) for(int i=a;i>=b;i--)
//#define local
typedef long long ll;
typedef unsigned long long ull;
const double esp = 1e-6;
const double pi = acos(-1.0);
const int INF = 0x3f3f3f3f;
const int inf = 1e9;
using namespace std;
ll read()
{
	char ch = getchar(); ll x = 0, f = 1;
	while (ch<'0' || ch>'9') { if (ch == '-')f = -1; ch = getchar(); }
	while (ch >= '0' && ch <= '9') { x = x * 10 + ch - '0'; ch = getchar(); }
	return x * f;
}
typedef pair<int, int> pir;
#define lson l,mid,root<<1
#define rson mid+1,r,root<<1|1
#define lrt root<<1
#define rrt root<<1|1
const int N = 2e5 + 10;
const int B = 30;
struct trie {
	int cnt = 1;
	int ch[N * 20][2];
	vector<int>vec[N * 20];
	void insert(int val) {
		int u = 1;
		dwd(i, B, 0) {
			if (val >> i & 1) {
				if (!ch[u][1])ch[u][1] = ++cnt;
				u = ch[u][1];
			}
			else {
				if (!ch[u][0])ch[u][0] = ++cnt;
				u = ch[u][0];
			}
			vec[u].push_back(val);
		}
	}
	ll query(int o, int x, int d) {
		if(d < 0)return 0;
		int bit = x >> d & 1;
		if (ch[o][bit])return query(ch[o][bit], x, d - 1);
		else return query(ch[o][bit ^ 1], x, d - 1) | (1 << d);	
	}
}T;
ll dfs(int o, int d) {
	if (!o || d < 0)return 0;
	int lf = T.ch[o][0];
	int rt = T.ch[o][1];
	ll res = 0;
	if (lf&&rt) {
		ll ans = (1 << (d + 1));
		for (auto k : T.vec[lf]) {
			ans = min(ans, T.query(rt, k, d - 1));
		}
		ans += (1 << d);
		res = ans;
	}
	return res + dfs(lf, d - 1) + dfs(rt, d - 1);
}
int n;
int a[N];
int main() {
	n = read();
	upd(i, 1, n)a[i] = read();
	sort(a + 1, a + n + 1);
	upd(i, 1, n)T.insert(a[i]);
	cout << dfs(1, B) << endl;
	return 0;
}