created custom hash function

susmitmishra125 · Feb 7, 2021 · 46fb952 · 46fb952
1 parent 1259020
commit 46fb952
Showing 1 changed file with 20 additions and 0 deletions.
diff --git a/custom_hash.cpp b/custom_hash.cpp
@@ -0,0 +1,20 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+struct custom_hash {
+    static uint64_t splitmix64(uint64_t x) {
+        // http://xorshift.di.unimi.it/splitmix64.c
+        x += 0x9e3779b97f4a7c15;
+        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
+        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
+        return x ^ (x >> 31);
+    }
+
+    size_t operator()(uint64_t x) const {
+        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
+        return splitmix64(x + FIXED_RANDOM);
+    }
+};
+
+
+int main(){}