PostgreSQL Source Code: src/backend/lib/bipartite_match.c Source File (original) (raw)
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19#include <limits.h>
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29#define HK_INFINITY SHRT_MAX
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40{
42
43 if (u_size < 0 || u_size >= SHRT_MAX ||
44 v_size < 0 || v_size >= SHRT_MAX)
45 elog(ERROR, "invalid set size for BipartiteMatch");
46
47 state->u_size = u_size;
48 state->v_size = v_size;
49 state->adjacency = adjacency;
50 state->matching = 0;
51 state->pair_uv = (short *) palloc0((u_size + 1) * sizeof(short));
52 state->pair_vu = (short *) palloc0((v_size + 1) * sizeof(short));
53 state->distance = (short *) palloc((u_size + 1) * sizeof(short));
54 state->queue = (short *) palloc((u_size + 2) * sizeof(short));
55
57 {
58 int u;
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60 for (u = 1; u <= u_size; u++)
61 {
62 if (state->pair_uv[u] == 0)
64 state->matching++;
65 }
66
68 }
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71}
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76
77void
79{
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86}
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92static bool
94{
95 int usize = state->u_size;
96 short *queue = state->queue;
97 short *distance = state->distance;
98 int qhead = 0;
99 int qtail = 0;
100 int u;
101
103
104 for (u = 1; u <= usize; u++)
105 {
106 if (state->pair_uv[u] == 0)
107 {
108 distance[u] = 0;
109 queue[qhead++] = u;
110 }
111 else
113 }
114
115 while (qtail < qhead)
116 {
117 u = queue[qtail++];
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119 if (distance[u] < distance[0])
120 {
121 short *u_adj = state->adjacency[u];
122 int i = u_adj ? u_adj[0] : 0;
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125 {
126 int u_next = state->pair_vu[u_adj[i]];
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129 {
130 distance[u_next] = 1 + distance[u];
131 Assert(qhead < usize + 2);
132 queue[qhead++] = u_next;
133 }
134 }
135 }
136 }
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139}
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145static bool
147{
148 short *distance = state->distance;
149 short *pair_uv = state->pair_uv;
150 short *pair_vu = state->pair_vu;
151 short *u_adj = state->adjacency[u];
152 int i = u_adj ? u_adj[0] : 0;
153 short nextdist;
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155 if (u == 0)
156 return true;
158 return false;
159 nextdist = distance[u] + 1;
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162
164 {
165 int v = u_adj[i];
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167 if (distance[pair_vu[v]] == nextdist)
168 {
170 {
171 pair_vu[v] = u;
172 pair_uv[u] = v;
173 return true;
174 }
175 }
176 }
177
179 return false;
180}
BipartiteMatchState * BipartiteMatch(int u_size, int v_size, short **adjacency)
static bool hk_depth_search(BipartiteMatchState *state, int u)
void BipartiteMatchFree(BipartiteMatchState *state)
static bool hk_breadth_search(BipartiteMatchState *state)
Assert(PointerIsAligned(start, uint64))
void pfree(void *pointer)
void * palloc0(Size size)
#define CHECK_FOR_INTERRUPTS()
void check_stack_depth(void)