#6850. 最大异或和

https://loj.ac/s/1661199

LibreOJ/6850/6850.cpp

@@ -0,0 +1,87 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 6e5 + 5;
+
+int n, m, sum;
+int cnt, tot, root[N], lst[N], tr[N << 5][2], siz[N << 5];
+
+void insert(int val) {
+    root[++tot] = ++cnt;
+
+    int l = root[tot - 1], r = root[tot];
+
+    for (int i = 30; i >= 0; i--) {
+        bool x = val >> i & 1;
+
+        tr[r][x ^ 1] = tr[l][x ^ 1];
+        tr[r][x] = ++cnt;
+
+        l = tr[l][x];
+        r = tr[r][x];
+
+        siz[r] = siz[l] + 1;
+    }
+
+    lst[tot] = cnt;
+}
+
+int query(int l, int r, int val) {
+    int res = 0;
+
+    l = root[l], r = root[r];
+
+    for (int i = 30; i >= 0; i--) {
+        bool x = val >> i & 1;
+
+        if (siz[tr[r][x ^ 1]] > siz[tr[l][x ^ 1]]) {
+            res |= 1 << i;
+            x = x ^ 1;
+        }
+
+        l = tr[l][x];
+        r = tr[r][x];
+    }
+
+    return res;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    insert(0);
+
+    for (int i = 1, x; i <= n; i++) {
+        cin >> x;
+
+        insert(sum ^= x);
+    }
+
+    while (m--) {
+        char op;
+
+        cin >> op;
+
+        if (op == 'A') {
+            int x;
+
+            cin >> x;
+
+            insert(sum ^= x);
+        } else {  // op == 'Q'
+            int l, r, x;
+
+            cin >> l >> r >> x;
+
+            cout << query(l - 1, r, x ^ sum) << endl;
+        }
+    }
+
+    return 0;
+}