Timothy Calford CalfordMath
CalfordMath
/ MathSheetFunctions.m
Last active
October 4, 2025 04:52
Helpful Lambda Functions for Math Worksheet Automation
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| // --- Workbook module --- | |
| // A file of name definitions of the form: | |
| // name = definition; | |
| //Gives just the slope through (xA, yA) and (xB, yB), | |
| //Optional: just numerator num_den = "num", just denominator num_den = "den", leave blank for full slope | |
| //Optional: decimal = True or False (false by default, true if you want the slope as a decimal) | |
| //Optional: reduced = True or False (true by default) | |
| slopeFromPoints = LAMBDA(xA, yA, xB, yB, [num_den], [decimal], [reduced], | |
| LET( |
CalfordMath
/ Minified Sudoku Solver
Last active
May 11, 2024 04:58
A 318 character Excel Lambda function that solves any sudoku puzzle fast
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| S=LAMBDA(p,LET(z,XMATCH(0,TOCOL(--p)),c,LAMBDA(c,x,IF(x>9,0,IF(NOT(OR(INDEX(p,INT((z-1)/9)+1,SEQUENCE(1,9))=x,INDEX(p,SEQUENCE(9),MOD(z-1,9)+1)=x,INDEX(p,SEQUENCE(3,1,INT(((z-1)/27))*3+1),SEQUENCE(1,3,FLOOR(MOD(z-1,9),3)+1))=x)),LET(r,S(IF(SEQUENCE(9,9,1)=z,x,p)),IF(AND(r),r,c(c,x+1))),c(c,x+1)))),IFERROR(c(c,1),p))); | |
| Or a slightly different, even faster solution (332 characters): | |
| S=LAMBDA(p,LET(n,SEQUENCE(9,9,0),z,XMATCH(0,TOCOL(--p))-1,g,LAMBDA(UNIQUE(VSTACK(SEQUENCE(9),TOCOL(INDEX(p,FLOOR(INT(z/9),3)+{1;2;3},FLOOR(MOD(z,9),3)+{1,2,3})),TOCOL(INDEX(p,INT(z/9)+1,)),INDEX(p,,MOD(z,9)+1)),,1)),c,LAMBDA(c,L,x,IF(x>ROWS(L),FALSE,LET(s,S(IF(n=z,INDEX(L,x),p)),IF(MIN(s)>0,s,c(c,L,x+1))))),IFERROR(c(c,g(),1),p))) | |
| //=S(A1:I9) or | |
| //=S({8,0,0,0,0,0,0,0,0;0,0,3,6,0,0,0,0,0;0,7,0,0,9,0,2,0,0;0,5,0,0,0,7,0,0,0;0,0,0,0,4,5,7,0,0;0,0,0,1,0,0,0,3,0;0,0,1,0,0,0,0,6,8;0,0,8,5,0,0,0,1,0;0,9,0,0,0,0,4,0,0}) | |
| //credits: |
CalfordMath
/ sudoku
Last active
April 24, 2024 19:39
— forked from lhem/sudoku
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| //ref: https://codereview.stackexchange.com/q/199771 | |
| //CalfordMath edit notes: | |
| //I placed the "test" lambda inside of "solver" to acheive a single Lambda function (nested recursive). | |
| //I'm not sure this optimizes anything computationally, and perhaps it makes the code less easy to follow, | |
| //but I find it satisfying to have everything wrapped in a single function :) | |
| solver = LAMBDA(grid, | |
| LET( |
CalfordMath
/ Sudoku Solver - Excel Formulas Only, (No VBA)
Last active
May 4, 2024 23:51
A Lambda Function with nested recursion that receives a 9x9 puzzle range (i.e. B2:J10) and outputs a 9x9 spilled range with the completed puzzle. No VBA. Just formulas. No specific cell references beyond the input range. It takes about 3 minutes and 3 seconds to solve the world's current hardest sudoku puzzle on an average fast computer. It inco…
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| Sudoku = LAMBDA(Puzzle, | |
| LET( | |
| Options, MAKEARRAY(27, 27, LAMBDA(r, c, MOD(c - 1, 3) + 1 + 3 * MOD(r - 1, 3))), | |
| numgrid, SEQUENCE(9, 9, 1), | |
| UpdatedPuzzle, LET( | |
| ApplyLogic, LAMBDA(ApplyLogic, Puzzle, Options, | |
| LET( | |
| Candidates, MAKEARRAY( | |
| 27, | |
| 27, |