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sort.hpp
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3  * Main authors:
4  * Christian Schulte <schulte@gecode.org>
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7  * Christian Schulte, 2002
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33 
34 #include <algorithm>
35 #include <climits>
36 
37 namespace Gecode { namespace Support {
38 
40  template<class Type, class Less>
41  forceinline void
42  exchange(Type &a, Type &b, Less &less) {
43  if (less(b,a)) std::swap(a,b);
44  }
45 
47  int const QuickSortCutoff = 20;
48 
50  template<class Type>
52  private:
54  static const int maxsize = sizeof(int) * CHAR_BIT;
56  Type** tos;
58  Type* stack[2*maxsize+1];
59  public:
61  QuickSortStack(void);
63  bool empty(void) const;
65  void push(Type* l, Type* r);
67  void pop(Type*& l, Type*& r);
68  };
69 
70  template<class Type>
72  QuickSortStack<Type>::QuickSortStack(void) : tos(&stack[0]) {
73  *(tos++) = NULL;
74  }
75 
76  template<class Type>
77  forceinline bool
79  return *(tos-1) == NULL;
80  }
81 
82  template<class Type>
83  forceinline void
84  QuickSortStack<Type>::push(Type* l, Type* r) {
85  *(tos++) = l; *(tos++) = r;
86  }
87 
88  template<class Type>
89  forceinline void
90  QuickSortStack<Type>::pop(Type*& l, Type*& r) {
91  r = *(--tos); l = *(--tos);
92  }
93 
95  template<class Type, class Less>
96  forceinline void
97  insertion(Type* l, Type* r, Less &less) {
98  for (Type* i = r; i > l; i--)
99  exchange(*(i-1),*i,less);
100  for (Type* i = l+2; i <= r; i++) {
101  Type* j = i;
102  Type v = *i;
103  while (less(v,*(j-1))) {
104  *j = *(j-1); j--;
105  }
106  *j = v;
107  }
108  }
109 
111  template<class Type, class Less>
112  forceinline Type*
113  partition(Type* l, Type* r, Less &less) {
114  Type* i = l-1;
115  Type* j = r;
116  Type v = *r;
117  while (true) {
118  while (less(*(++i),v)) {}
119  while (less(v,*(--j))) if (j == l) break;
120  if (i >= j) break;
121  std::swap(*i,*j);
122  }
123  std::swap(*i,*r);
124  return i;
125  }
126 
128  template<class Type, class Less>
129  inline void
130  quicksort(Type* l, Type* r, Less &less) {
132  while (true) {
133  std::swap(*(l+((r-l) >> 1)),*(r-1));
134  exchange(*l,*(r-1),less);
135  exchange(*l,*r,less);
136  exchange(*(r-1),*r,less);
137  Type* i = partition(l+1,r-1,less);
138  if (i-l > r-i) {
139  if (r-i > QuickSortCutoff) {
140  s.push(l,i-1); l=i+1; continue;
141  }
142  if (i-l > QuickSortCutoff) {
143  r=i-1; continue;
144  }
145  } else {
146  if (i-l > QuickSortCutoff) {
147  s.push(i+1,r); r=i-1; continue;
148  }
149  if (r-i > QuickSortCutoff) {
150  l=i+1; continue;
151  }
152  }
153  if (s.empty())
154  break;
155  s.pop(l,r);
156  }
157  }
158 
160  template<class Type>
161  class Less {
162  public:
163  bool operator ()(const Type& lhs, const Type& rhs) {
164  return lhs < rhs;
165  }
166  };
167 
183  template<class Type, class Less>
184  forceinline void
185  insertion(Type* x, int n, Less &l) {
186  if (n < 2)
187  return;
188  assert(!l(x[0],x[0]));
189  insertion(x,x+n-1,l);
190  }
191 
203  template<class Type>
204  forceinline void
205  insertion(Type* x, int n) {
206  if (n < 2)
207  return;
208  Less<Type> l;
209  assert(!l(x[0],x[0]));
210  insertion(x,x+n-1,l);
211  }
212 
228  template<class Type, class Less>
229  forceinline void
230  quicksort(Type* x, int n, Less &l) {
231  if (n < 2)
232  return;
233  assert(!l(x[0],x[0]));
234  if (n > QuickSortCutoff)
235  quicksort(x,x+n-1,l);
236  insertion(x,x+n-1,l);
237  }
238 
250  template<class Type>
251  forceinline void
252  quicksort(Type* x, int n) {
253  if (n < 2)
254  return;
255  Less<Type> l;
256  assert(!l(x[0],x[0]));
257  if (n > QuickSortCutoff)
258  quicksort(x,x+n-1,l);
259  insertion(x,x+n-1,l);
260  }
261 
262 }}
263 
264 // STATISTICS: support-any
Post propagator for SetVar x
Definition: set.hh:767
Type * partition(Type *l, Type *r, Less &less)
Standard partioning.
Definition: sort.hpp:113
Static stack for quicksort.
Definition: sort.hpp:51
void pop(Type *&l, Type *&r)
Pop two positions l and r.
Definition: sort.hpp:90
void quicksort(Type *l, Type *r, Less &less)
Standard quick sort.
Definition: sort.hpp:130
Gecode toplevel namespace
void insertion(Type *l, Type *r, Less &less)
Standard insertion sort.
Definition: sort.hpp:97
bool empty(void) const
Test whether stack is empty.
Definition: sort.hpp:78
Post propagator for SetVar SetOpType SetVar SetRelType r
Definition: set.hh:767
IntRelType swap(IntRelType irt)
Return swapped relation type of irt.
Definition: irt.hpp:37
struct Gecode::@602::NNF::@65::@66 b
For binary nodes (and, or, eqv)
bool operator()(const Type &lhs, const Type &rhs)
Definition: sort.hpp:163
struct Gecode::@602::NNF::@65::@67 a
For atomic nodes.
const int v[7]
Definition: distinct.cpp:259
NNF * l
Left subtree.
Definition: bool-expr.cpp:240
const int QuickSortCutoff
Perform quicksort only for more elements.
Definition: sort.hpp:47
#define forceinline
Definition: config.hpp:185
Comparison class for sorting using <.
Definition: sort.hpp:161
QuickSortStack(void)
Initialize stack as empty.
Definition: sort.hpp:72
int n
Number of negative literals for node type.
Definition: bool-expr.cpp:234
Gecode::IntArgs i({1, 2, 3, 4})
void push(Type *l, Type *r)
Push two positions l and r.
Definition: sort.hpp:84
void exchange(Type &a, Type &b, Less &less)
Exchange elements according to order.
Definition: sort.hpp:42