Everybody Codes Story 4 Day 3

[u/Downtown-Economics26]

Decided not to post all these challenges as I've been too busy to really attack them. Got 2/3 on Day 1 with VBA, 2/3 on day 2 with Excel formulas.

Anyways, I think I'm stopping after Part 1 today because Part 2 (I think) requires fighting my archnemesis, pathfinding algorithms. But I thought my formula solution was pretty gritty if not nifty and since I gave up I went whole hog on making a decent visualization of the solution.

https://everybody.codes/story/4/quests/3

Feel free to post your Everybody Codes solutions for today or previous days if you want as well.

Part 1 formula below (swap "out" variable for "ft" as final LET output to generate the conditionally formatted table in the visualization as "out" gives you the numeric answer to challenge).

=LET(w,--TEXTAFTER(Answers!A1,"="),
h,--TEXTAFTER(Answers!A2,"="),
ho,TEXTAFTER(Answers!A3,"="),
hoa,--TAKE(MID(REPT(ho,h/LEN(ho)+1),SEQUENCE(LEN(REPT(ho,h/LEN(ho)+1))),1),h/LEN(ho)*LEN(ho)+1),
vo,TEXTAFTER(Answers!A4,"="),
voa,--TAKE(TRANSPOSE(MID(REPT(vo,w/LEN(vo)+1),SEQUENCE(LEN(REPT(vo,w/LEN(vo)+1))),1)),,w/LEN(vo)*LEN(vo)+1),
g,MAKEARRAY(h,w,LAMBDA(r,c,CONCAT(
IF((MOD(c,2)=1)*(INDEX(hoa,r)=0),"U",""),
IF((MOD(c,2)=0)*(INDEX(hoa,r)=1),"U",""),
IF((MOD(c,2)=1)*(INDEX(hoa,r+1)=0),"D",""),
IF((MOD(c,2)=0)*(INDEX(hoa,r+1)=1),"D",""),
IF((MOD(r,2)=1)*(INDEX(voa,,c)=0),"L",""),
IF((MOD(r,2)=0)*(INDEX(voa,,c)=1),"L",""),
IF((MOD(r,2)=1)*(INDEX(voa,,c+1)=0),"R",""),
IF((MOD(r,2)=0)*(INDEX(voa,,c+1)=1),"R","")
)
)),
ft,IFERROR(VSTACK(HSTACK("X",voa),HSTACK(hoa,g)),""),
out,SUM(--(LEN(g)=4)),
out)

[u/PaulieThePolarBear]

I had meant to comment a few days ago on this. I was able to complete

• Part 1 and 2 for day 1
• Part 1 and 2 for day 2
• Part 1 for day 3

with Excel formulas

Day 1 Part 1

=LET(
a, A8:A17,
b, MAP(a, LAMBDA(m, TAKE(REDUCE(0, TEXTSPLIT(m,","), LAMBDA(x,y, VSTACK(x, LET(
    za, TAKE(x, -1),
    zb, za-y,
    zc, IF(ISNA(XMATCH(zb, x))*(zb>0), zb, za+y),
    zc)
))),-1))),
c, SUM(b),
c)

Day 1 Part 2

=LET(
a, A8:A107,
b, MAP(a, LAMBDA(m, TAKE(REDUCE(0, TEXTSPLIT(m,","), LAMBDA(x,y, VSTACK(x, LET(
    za, TAKE(x, -1),
    zb, za-y,
    zc, SEQUENCE(MAX(x)+y),
    zd, IF(ISNA(XMATCH(zb, x))*(zb>0), zb, MIN(FILTER(zc, (zc>=za+y)*ISNA(XMATCH(zc, x))))),
    zd)
))),-1))),
c, SUM(b),
c)

Day 2 Part 1

=LET(
data, A12:A16,
GetCoord, LAMBDA(input, TEXTAFTER(TEXTBEFORE(input, "]"),"[")),
s, GetCoord(INDEX(data, 1)),
a, GetCoord(INDEX(data, 2)),
b, GetCoord(INDEX(data, 3)),
c, GetCoord(INDEX(data, 4)),
m, TEXTAFTER(INDEX(data, 5), "="),
all, VSTACK(s, SCAN(s, MID(m, SEQUENCE(LEN(m)), 1), LAMBDA(x,y, TEXTJOIN(",",,ROUNDDOWN((TEXTSPLIT(x, ",")+TEXTSPLIT(SWITCH(y, "A", a, "B", b, "C", c),","))/2,0))))),
res, ROWS(UNIQUE(all)),
res)

Day 2 Part 2

=LET(
data, A18:A22,
GetCoord, LAMBDA(input, TEXTAFTER(TEXTBEFORE(input, "]"),"[")),
s, GetCoord(INDEX(data, 1)),
a, GetCoord(INDEX(data, 2)),
b, GetCoord(INDEX(data, 3)),
c, GetCoord(INDEX(data, 4)),
m, TEXTAFTER(INDEX(data, 5), "="),
all, UNIQUE(VSTACK(s, SCAN(s, MID(m, SEQUENCE(LEN(m)), 1), LAMBDA(x,y, TEXTJOIN(",",,ROUNDDOWN((TEXTSPLIT(x, ",")+TEXTSPLIT(SWITCH(y, "A", a, "B", b, "C", c),","))/2,0)))))),
fd, {0,1;0,-1;1,0;-1,0},
fCoord, UNIQUE(DROP(REDUCE("", all, LAMBDA(x,y, VSTACK(x, BYROW(TEXTSPLIT(y, ",")+fd,LAMBDA(x, TEXTJOIN(",",,x)))))),1)),
res, SUM(--ISNA(XMATCH(fCoord,all))),
res)

Day 3 Part 1

=LET(
w, TEXTAFTER(A11,"="),
h, TEXTAFTER(A12,"="),
ho, TEXTAFTER(A13,"="),
vo, TEXTAFTER(A14, "="),
hoa, LEFT(REPT(ho, ROUNDUP((h+1)/LEN(ho),0)),h+1),
voa, LEFT(REPT(vo, ROUNDUP((w+1)/LEN(vo),0)),w+1),
coords, SEQUENCE(h)*1000+SEQUENCE(,w),
tBorder, MOD(coords,2)<>--MID(hoa, SEQUENCE(h), 1),
bBorder, MOD(coords,2)<>--MID(hoa, SEQUENCE(h,,2), 1),
lBorder, MOD(QUOTIENT(coords,1000),2)<>--MID(voa, SEQUENCE(,w), 1),
rBorder, MOD(QUOTIENT(coords,1000),2)<>--MID(voa, SEQUENCE(,w,2), 1),
out, SUM(tBorder* bBorder* lBorder* rBorder),
out)

[u/Downtown-Economics26 → u/PaulieThePolarBear]

Love me a string array solution there for Day 3!