xorshift

Author: tsutaj

marathon/rand_xorshift.cpp

@@ -0,0 +1,28 @@
+#include <cstdint>
+
+struct Rand {
+ private:
+  constexpr static double R = 1.0 / 0xffffffff;
+  uint64_t x;
+
+ public:
+  Rand(uint64_t seed = 88172645463325252ull) : x(seed) {}
+
+  inline uint64_t nextULong() {  // [0, 2^64)
+    x ^= x << 7ull;
+    x ^= x >> 9ull;
+    return x;
+  }
+
+  inline uint32_t nextUInt(uint32_t r) {  // [0, r)
+    return ((nextULong() >> 32ull) * r) >> 32ull;
+  }
+
+  inline uint32_t nextUInt(uint32_t l, uint32_t r) {  // [l, r)
+    return l + nextUInt(r - l);
+  }
+
+  inline double nextDouble() {  // [0.0, 1.0]
+    return ((uint32_t)nextULong()) * R;
+  }
+};

marathon/template.cpp

@@ -108,7 +108,7 @@ bool chmax(Tp& a, const Tp& b) {
 }
 
 #include "/home/tsutaj/Documents/compro/cpp_library/marathon/timer.cpp"
-#include "/home/tsutaj/Documents/compro/cpp_library/marathon/rand.cpp"
+#include "/home/tsutaj/Documents/compro/cpp_library/marathon/rand_xorshift.cpp"
 Rand rnd(35023503980LL);
 Timer timer;
 using Answer = vector<int>; // TODO
@@ -134,5 +134,6 @@ int main() {
     timer.setStart();
     input();
     solve();
+    fprintf(stderr, "end time = %.3f\n", timer.getTime());
     return 0;
 }