path: root/main.cpp

#include <iostream>
#include <cstdlib>
#include <random>
#include <cstring>
#include <ctime>

template<typename T>
inline void swap(T &a, T &b) {
  T t = a;
  a = b;
  b = t;
}

template<typename T>
inline void insert(T *l, T *r, int (*compar)(const void*, const void*)) {
  T* s = l;
  while (s<r) {
    T* k = s+1;
    while (k > l && compar(k,k-1) < 0) {
      swap(*k, *(k-1));
      --k;
    }
    ++s;
  }
}

#define INS 12

template<typename T>
void secret1(T *l, T *r, int (*compar)(const void*, const void*)) {
  T *j = r;
  T *i = l+1;
  {
    int a = compar(l, l+1), b= compar(l,l+2), c = compar(l+1,l+2);
    if (a > 0) {
      if (b > 0)
      if (c<0) swap(*l,l[2]);
        else swap(*l,l[1]);
    } else if (a < 0) {
      if (b < 0)
        if (c<0) swap(*l,l[1]);
        else swap(*l,l[2]);
    }
  }
  while (i <= j) {
    int a = compar(l,i);
    if (a <= 0) {
      int b = 0;
      while (j > l && (b = compar(l,j)) < 0)
        --j;
      if (j > i) {
        if (a != b) {
          swap(*j, *i);
          --j;
        } else {
          --i; --j;
        }
      } else break;
    } else {
      ++i;
    }
  }
  swap(*l, *j);
  --j;
  //std::cout<< j-l <<" " << r-i << std::endl;
  if (l+INS < j)
    secret1(l,j, compar);
  else
    insert(l,j,compar);
  if (i+INS < r)
    secret1(i,r, compar);
  else
    insert(i,r,compar);
}

inline void swapsize(char *a,char *b, size_t size) {
  for (int cnt = 0; cnt < size; ++cnt)
    swap<char>(a[cnt],b[cnt]);
}

void secret(char *l, char *r, size_t size,int (*compar)(const void*, const void*)) {
  char *j = r;
  char *i = l+size;
  while (i <= j) {
    if (compar(l,i) < 0) {
      swapsize(j, i, size);
      j -= size;
    } else {
      i += size;
    }
  }
  swapsize(l, j, size);
  j -= size;
  if (l < j)
    secret1(l, j, compar);
  if (i < r)
    secret1(i, r, compar);

}

void mqsort(void* base, size_t num, size_t size, int (*compar)(const void*, const void*)) {
  switch (size) {
    case 1:
      secret1((uint8_t*)base, (uint8_t*)base+(num-1), compar);
      break;
    case 2:
      secret1((uint16_t *)base, (uint16_t *)base+(num-1), compar);
      break;
    case 4:
      secret1((uint32_t *)base, (uint32_t*)base+(num-1), compar);
      break;
    case 8:
      secret1((uint64_t *)base, (uint64_t *)base+(num-1), compar);
      break;
    default:
      secret((char*)base, (char*)base+(num-1)*size, size, compar);
  }
}

template<typename T>
int compr(const void * a, const void * b){
  T aa = *(T*)a;
  T bb = *(T*)b;
  if (aa > bb)
    return 1;
  if (aa < bb)
    return -1;
  return 0;
}

template<typename T>
void* genInt(size_t num) {
  std::random_device r;
  std::mt19937_64 e(r());
  std::uniform_int_distribution<T> unifrom_dist(0, 1 << (sizeof(T)*8 -2));
  T * res = (T*)malloc(num * sizeof(T));
  for (size_t i = 0; i<num; ++i)
    res[i] = unifrom_dist(e);
  return res;
}

template<typename T>
void* genFloat(size_t num) {
  std::random_device r;
  std::mt19937_64 e(r());
  std::uniform_real_distribution<T> unifrom_dist(0, 1);
  T * res = (T*)malloc(num * sizeof(T));
  for (size_t i = 0; i<num; ++i)
    res[i] = unifrom_dist(e);
  return res;
}

template<typename T>
void* gen(size_t num) {
  return genInt<T>(num);
}

template <>
void* gen<float>(size_t num) {
  return genFloat<float>(num);
}

template <>
void* gen<double>(size_t num) {
  return genFloat<double>(num);
}

int compeq(uint32_t *a,uint32_t *b, size_t size) {
  for (size_t i = 0; i< size; ++i)
    if (a[i] != b[i])
      return 1;
  return 0;
}

template<typename T>
void print(void *v, size_t num) {
  T * k = (T*) v;
  for (int i = 0; i<num; ++i)
    std::cout<< k[i] << " ";
  std::cout<<std::endl;
}

template<typename T>
void runAndTest(size_t num) {
  clock_t tst;
  clock_t tmd;
  clock_t ted;
  size_t size = sizeof(T);
  void *base = gen<T>(num);
  void *base2 = malloc(num*size);
  memcpy(base2,base,num*size);
  tst = clock();
  mqsort(base,num,size,compr<T>);
  tmd = clock();
  qsort(base2,num,size,compr<T>);
  ted = clock();
  if (compeq((uint32_t*)base,(uint32_t*)base2,num*size/4)) {
    std::cout << "Not equal" << std::endl;
    print<T>(base, num);
    print<T>(base2,num);
  }
  else
    std::cout<<"Equal"<<std::endl;
  std::cout<<"Time taken for me  : " << float(tmd - tst) / CLOCKS_PER_SEC<<std::endl;
  std::cout<<"Time taken for std : " << float(ted - tmd) / CLOCKS_PER_SEC<<std::endl;
}

void usage() {
  std::cout << "Usage: <this> [TYPE] [LENGTH]" <<std::endl;
  std::cout << "    [TYPE]" <<std::endl;
  std::cout << "          i : int" <<std::endl;
  std::cout << "          l : long" <<std::endl;
  std::cout << "          f : float" <<std::endl;
  std::cout << "          d : double" <<std::endl;
  std::cout << "    [LENGTH]" <<std::endl;
  std::cout << "          An int specify the number of elements in the list to be sorted" <<std::endl;
}

int main(int argc,char** argv) {
  if (argc < 3) {
    usage();
    return -1;
  }
  size_t num;
  try {
    num = (size_t)std::stoi(argv[2]);
  } catch (std::exception &e) {
    std::cout << e.what() << std::endl;
    usage();
    return -1;
  }
  switch(argv[1][0]) {
    case 'i':
      runAndTest<int>(num);
      break;
    case 'l':
      runAndTest<long>(num);
      break;
    case 'f':
      runAndTest<float>(num);
      break;
    case 'd':
      runAndTest<double>(num);
      break;
    default:
      usage();
      return -1;
  }
  return 0;
}