模仿主席树的思路打了一个代码。
每一个点插入以后合并，查询的时候要注意一下边界问题就好。

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;
const int N = 6e5 + 10, M = N * 32;

int cnt, trie[M][2], rt[N];

int n, m;

void insert(int p, int x) {
    for (int i = 30; i >= 0; i--)
        trie[p][x >> i & 1] = ++cnt, p = cnt;
}

void merge(int &x, int y) {
    if (!x) { x = y; return;}
    if (!y) return;
    merge(trie[x][0], trie[y][0]);
    merge(trie[x][1], trie[y][1]);
}

int calc(int l, int r, int x) {
    int ans = 0;
    for (int i = 30; i >= 0; i--) {
        int p = x >> i & 1;
        if (trie[l][p ^ 1] != trie[r][p ^ 1]) ans += (1 << i), l = trie[l][p ^ 1], r = trie[r][p ^ 1];
        else if (trie[r][p]) l = trie[l][p], r = trie[r][p];
        else break;
    }
    return ans;
}

int main() {
    rt[0] = ++cnt, insert(rt[0], 0);
    cin >> n >> m; int now = 0;
    for (int i = 1; i <= n; i++) {
        int x; scanf("%d", &x); now ^= x;
        rt[i] = ++cnt, insert(rt[i], now);
        merge(rt[i], rt[i - 1]);
    }
    while (m--) {
        char s[5]; scanf("%s", s);
        if (s[0] == 'A') {
            int x; scanf("%d", &x); now ^= x;
            rt[++n] = ++cnt; insert(rt[n], now);
            merge(rt[n], rt[n - 1]);
        }
        else {
            int l, r, x; scanf("%d%d%d", &l, &r, &x);
            x ^= now;
            if (r == 1) { printf("%d\n", x); continue;}
            int ans = calc(l > 1 ? rt[l - 2] : rt[l - 1], rt[r - 1], x);
            printf("%d\n", l > 1 ? ans : max(ans, x));
        }
    }
    return 0;
}