advent-of-code/18/18.awk

189 lines
3.1 KiB
Awk

function parse( s ){
delete sl; delete sr
while(length(s)>0){
if(match(s,/^[0-9]+/)){
num[++pindex] = substr(s,RSTART,RLENGTH)
s = substr(s,RSTART+RLENGTH)
continue
}
else if(s~/^\]/){ # ]
l = sl[slp--]
r = pindex
# print "left",l,"right",r
num[++pindex] = -1
ile[pindex] = l
iri[pindex] = r
if(slp==0) root = pindex
}
else if(s~/^,/){ # ,
sl[++slp] = pindex
}
s = substr(s,2)
}
}
function cleanparse(s){
delete ile; delete iri; delete num; delete sl
slp = 0
pindex = 0
parse(s)
}
function parent(id){
for(i in ile)
if(ile[i]==id || iri[i]==id) return i
return -1
}
function levels(id){
i = id
count = 0
if(id==root) return 0
do{
i = parent(i)
if(i<0) return -1
count++
}while(i!=root)
return count
}
function treetostring(id){
if(num[id]<0)
return "[" treetostring(ile[id]) "," treetostring(iri[id]) "]"
else
return num[id]
}
function leftitemi(id){
do{
id--
}while((num[id]<0 && id>0))
return id
}
function rightitemi(id){
do{
id++
}while((num[id]<0 && id<=length(num)))
return id
}
function explode(id){
lefti = leftitemi(id)
if(lefti>0){
num[lefti] += num[id]
num[id]=-1
}
righti = rightitemi(id)
rightrighti = rightitemi(righti)
if(rightrighti<=length(num)){
num[rightrighti] += num[righti]
num[righti] = -1
}
p = parent(id)
num[p] = 0
}
function toexplode(){
for(id=1;id<=pindex;id++){
if((num[id]>=0) && (levels(id)>4) && num[parent(id)]<0) return id
}
return -1
}
function dosplit(id){
n = num[id]
nl = int(n/2)
nr = int(n/2) + n%2
num[id] = -1
num[++pindex] = nl
ile[id] = pindex
num[++pindex] = nr
iri[id] = pindex
}
function tosplit(){
for(id=1;id<=pindex;id++){
# print id, (num[id]-10>0), num[id]
if((num[id]-10>=0) && num[parent(id)]<0 ) return id
}
return -1
}
function reduce(){
do{
ind = toexplode()
print "explode?", ind, num[ind], parent(ind), num[parent(ind)],num[leftitemi(ind)]
if(ind>0){
explode(ind)
print "exploded", treetostring(root)
s = treetostring(root)
cleanparse(s)
# print "to split?",tosplit()
continue
}
ind = tosplit()
print "split?", ind, num[ind], parent(ind), num[parent(ind)], ile[parent(ind)], iri[parent(ind)]
if(ind>0){
dosplit(ind)
print "split", treetostring(root)
s = treetostring(root)
cleanparse(s)
}
print toexplode(), tosplit()
} while( ((toexplode()>0) || (tosplit()>0)) )
print "done"
}
function magnitude(id){
if(num[id]>=0) return num[id] # regular number
# node
return magnitude(ile[id])*3 + magnitude(iri[id])*2
}
BEGIN{ pindex = 0 }
NR==1{
parse($0)
proot = root
}
NR>1{
parse( $0 )
num[++pindex] = -1
ile[pindex] = proot
iri[pindex] = root
root = pindex
print "raw add",NR, treetostring(root)
reduce()
s = treetostring(root)
cleanparse(s)
proot = root
print "after",NR,treetostring(root)
}
END{
OFS=":"
print pindex, root
# for(i in num)
# print i,num[i],levels(i)
# print "l,r, root:", root
# for(i in ile)
# print i, ile[i], iri[i]
# print num[1], "is at",levels(1),"levels"
s = treetostring(root)
cleanparse(s)
print treetostring(root)
reduce()
print treetostring(root)
print magnitude(root)
}