feat: enhanced performance

Author: a1fredbao

src/alfred/data_structure/hashmap.hpp

@@ -5,6 +5,8 @@
 #include <utility>
 #include <vector>
 
+std::vector<bool> s;
+
 template <class K, class V>
 struct HashMap { // HashMap for integer keys.
     using u32 = unsigned int;
@@ -23,7 +25,7 @@ struct HashMap { // HashMap for integer keys.
         fi.assign(lim, 0), tot = 0;
         mask = lim - 1, e.resize(sz);
     }
-    inline void inc(K x, V delta) {
+    inline void inc(K x, const V &delta) {
         u32 u = hash(x) & mask;
         for (u32 i = fi[u]; i; i = e[i].ne) {
             if (e[i].key == x) {

src/alfred/data_structure/splitmix.hpp

@@ -4,7 +4,7 @@
 template <class T>
 struct Splitmix {
     inline T operator()(T x) {
-        if constexpr (sizeof(T) == 8) {
+        if (sizeof(T) == 8) {
             T z = (x += 0x9e3779b97f4a7c15);
             z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
             z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
@@ -18,4 +18,29 @@ struct Splitmix {
     }
 };
 
+// use specialized version for 64bit and 32bit for older c++ standards
+// as if constexpr is not supported
+
+template <>
+struct Splitmix<unsigned long long> {
+    unsigned long long z;
+    inline unsigned long long operator()(unsigned long long x) {
+        z = (x += 0x9e3779b97f4a7c15);
+        z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
+        z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
+        return z ^ (z >> 31);
+    }
+};
+
+template <>
+struct Splitmix<unsigned int> {
+    unsigned int z;
+    inline unsigned int operator()(unsigned int x) {
+        z = (x += 0x9e3779b9);
+        z = (z ^ (z >> 16)) * 0x85ebca6b;
+        z = (z ^ (z >> 13)) * 0xc2b2ae35;
+        return z ^ (z >> 16);
+    }
+};
+
 #endif