abc451 binary trie fix

data_structure/binary_trie.hpp

@@ -85,6 +85,8 @@ template <class Int, class Count = int> struct BinaryTrie {
 
     // Count elements y such that x ^ y < thres
     Count count_less_xor(Int x, Int thres) const {
+        if (thres <= 0) return Count();
+        if ((thres >> maxD) > 0) return subtree_sum[0];
         Count ret = Count();
         int now = 0;
 

data_structure/binary_trie.md

@@ -26,3 +26,4 @@ Key v = bt.xor_min(t);  // t ^ x （x は現在存在する値）の最小値を
 
 - [Library Checker: Set Xor-Min](https://judge.yosupo.jp/problem/set_xor_min)
 - [No.2977 Kth Xor Pair - yukicoder](https://yukicoder.me/problems/no/2977)
+- [AtCoder Beginner Contest 451 G - Minimum XOR Walk](https://atcoder.jp/contests/abc451/tasks/abc451_g)

number/primitive_root.hpp

@@ -16,15 +16,15 @@
 //  - 163577857 ( = (39 << 22) + 1 ) -> 23
 //  - 2 -> 1
 //  - 1 -> -1
-long long find_smallest_primitive_root(long long n) {
+inline long long find_smallest_primitive_root(long long n) {
     std::vector<long long> fac;
     const long long phi = FactorizeLonglong.euler_phi(n);
     for (long long q : FactorizeLonglong(phi)) {
         if (fac.empty() or fac.back() != q) fac.push_back(q);
     }
 
     for (long long g = 1; g < n; g++) {
-        if (std::__gcd(n, g) != 1) continue;
+        if (std::gcd(n, g) != 1) continue;
         if (pow_mod<long long, __int128>(g, phi, n) != 1) return -1;
         bool ok = true;
         for (auto pp : fac) {

number/test/binary_gcd.stress.test.cpp

@@ -1,13 +1,13 @@
 #define PROBLEM "https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ITP1_1_A" // DUMMY
 #include "../binary_gcd.hpp"
-#include <algorithm> // __gcd
 #include <iostream>
+#include <numeric>
 using namespace std;
 
 template <typename Int> void test_binary_gcd(Int lo, Int hi) {
     for (Int x = lo; x <= hi; x++) {
         for (Int y = lo; y <= hi; y++) {
-            auto g = __gcd<Int>(x, y);
+            auto g = gcd<Int>(x, y);
             if (g < 0) g = -g;
             if (binary_gcd(x, y) != g) {
                 cerr << "Did not match : (x, y) = " << x << ',' << y << ')' << endl;

number/test/zeta_moebius_transform.test.cpp

@@ -3,6 +3,7 @@
 #include "../../modint.hpp"
 #include <cassert>
 #include <iostream>
+#include <numeric>
 #include <vector>
 using namespace std;
 
@@ -77,7 +78,7 @@ void test_gcdconv() {
             vector<mint> x = vecgen(n), y = vecgen(n), z(n + 1);
             auto conv = gcdconv(x, y);
             for (int i = 1; i <= n; ++i) {
-                for (int j = 1; j <= n; ++j) z[__gcd(i, j)] += x[i] * y[j];
+                for (int j = 1; j <= n; ++j) z[gcd(i, j)] += x[i] * y[j];
             }
             assert(conv == z);
         }
@@ -91,7 +92,7 @@ void test_lcmconv() {
             auto conv = lcmconv(x, y);
             for (int i = 1; i <= n; ++i) {
                 for (int j = 1; j <= n; ++j) {
-                    int l = i * j / __gcd(i, j);
+                    int l = i * j / gcd(i, j);
                     if (l <= n) z[l] += x[i] * y[j];
                 }
             }