From b1fdc7d76eda029cfeef490f6f737166c1c72828 Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Sun, 26 Feb 2023 08:39:10 +0800
Subject: [PATCH] =?UTF-8?q?P3812=20=E3=80=90=E6=A8=A1=E6=9D=BF=E3=80=91?=
 =?UTF-8?q?=E7=BA=BF=E6=80=A7=E5=9F=BA?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

https://www.luogu.com.cn/record/103041260
---
 Luogu/P3812/P3812.cpp        | 63 +++++++++++++++++++++++-------------
 Luogu/P3812/data/P3812_2.in  |  3 ++
 Luogu/P3812/data/P3812_2.out |  3 ++
 3 files changed, 46 insertions(+), 23 deletions(-)
 create mode 100644 Luogu/P3812/data/P3812_2.in
 create mode 100644 Luogu/P3812/data/P3812_2.out

diff --git a/Luogu/P3812/P3812.cpp b/Luogu/P3812/P3812.cpp
index 17e2d2f7..be123ff5 100644
--- a/Luogu/P3812/P3812.cpp
+++ b/Luogu/P3812/P3812.cpp
@@ -1,50 +1,67 @@
 #include <iostream>
+#include <algorithm>
+#include <iterator>
+#include <limits>
+#include <type_traits>
 
 using std::cin;
 using std::cout;
 const char endl = '\n';
 
-const int N = 55;
+const int N = 1e5 + 5;
 
-int n;
-long long x, a[N], ans;
+template <typename T>
+struct LinearBasis
+    : std::enable_if<std::is_unsigned<T>::value, T> {
+    T a[std::numeric_limits<T>::digits];
 
-void insert(long long x) {
-    for (int i = 50; ~i; i--) {
-        if (!(x & (1ll << i))) continue;
+    LinearBasis() {
+        std::fill(std::begin(a), std::end(a), 0);
+    }
 
-        if (a[i]) {
-            x ^= a[i];
-        } else {
-            for (int k = 0; k < i; k++) {
-                if (x & (1ll << k)) x ^= a[k];
+    void insert(unsigned long long x) {
+        for (int i = std::numeric_limits<T>::digits - 1; ~i; i--) {
+            if ((x >> i) & 1) {
+                if (a[i]) {
+                    x ^= a[i];
+                } else {
+                    a[i] = x;
+
+                    return;
+                }
             }
-
-            for (int k = i + 1; k <= 50; k++) {
-                if (a[k] & (1ll << i)) a[k] ^= x;
-            }
-
-            a[i] = x;
-            return;
         }
     }
-}
+
+    T query() {
+        T res(0);
+
+        for (int i = std::numeric_limits<T>::digits - 1; ~i; i--) {
+            if ((res ^ a[i]) > res) res ^= a[i];
+        }
+
+        return res;
+    }
+};
 
 int main() {
     std::ios::sync_with_stdio(false);
     cin.tie(nullptr);
 
+    int n;
+    LinearBasis<unsigned long long> lb;
+
     cin >> n;
 
     for (int i = 1; i <= n; i++) {
+        unsigned long long x;
+
         cin >> x;
 
-        insert(x);
+        lb.insert(x);
     }
 
-    for (int i = 0; i <= 50; i++) ans ^= a[i];
-
-    cout << ans << endl;
+    cout << lb.query() << endl;
 
     return 0;
 }
diff --git a/Luogu/P3812/data/P3812_2.in b/Luogu/P3812/data/P3812_2.in
new file mode 100644
index 00000000..9438f5eb
--- /dev/null
+++ b/Luogu/P3812/data/P3812_2.in
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3eb2393f3e4c271017cc102d424a434e64ddd32e2867fc1412bb6ce72206d7a7
+size 164
diff --git a/Luogu/P3812/data/P3812_2.out b/Luogu/P3812/data/P3812_2.out
new file mode 100644
index 00000000..6e230e2d
--- /dev/null
+++ b/Luogu/P3812/data/P3812_2.out
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:481f710584ea6eff9ff793f84e9ca21ae379271f01ce714c667a2562f70ce690
+size 17