algorithm - Brute force magic squares -

-

basically have 3 x 3 grid filled 2 digit numbers 00 - 99. of numbers given input rest unknown. suggestions on how solve such problem brute force in c?

edit: sorry forgot part of problem. every row , column , diagonal must add same number. don't want code ideas started algorithm

there simple recursive solution problem, example of type of brute force called backtracking (google that).

the recursive function (say, fill_next) finds next cell unknown value. if there no such cell, checks square see if fits requirements (the sums correct) , if prints square solution; returns. if there cell unknown value, loops, trying each of values 0 99 in turn cell calling recursively fill in next unknown cell.

how next cell unknown value: can pass find_next number of next cell start looking at; start whole thing off calling fill_next(0). cell number 0 through 8 since have 9 cells. if storing square in 2d array, use num%3 , num/3 indices.

this easier describe giving few lines of code takes, said don't want that.


Comments

Post a Comment

Popular posts from this blog

javascript - Enclosure Memory Copies -

-
function myclass() { //lots , lots of vars , code here. this.bar = function() { //do numerous enclosed myclass vars } this.foo = function() { alert('hello'); //don't enclosed variables. } } each instance of myclass gets own copy of bar , foo, why prototyped methods use less memory. however, know more memory use of inner methods. it seems obvious me (1) below must true. agree? not distinct myclass instances have own distinct copies of bar, must have own distinct copies of myclass enclosure. (or else how bar method keep myclass variables straight on per instance basis?) now (2) question i'm after. since inner foo method doesn't use in myclass enclosure natural qustion is: javascript smart enough not keep myclass enclosure in memory use of foo? this depend entirely on implementation not language. naive implementations keep far more around others. answer true e.g. v8 (chrome's js engine) may not true spider...
Read more

php - Replacing tags in braces, even nested tags, with regex -

-
example preg_replace('/\{[a-za-z.,\(\)0-9]+\}/', 'replaced', 'lorem ipsum dolor sit {tag1({tag2()})}, consectetur adipiscing elit.'); the result: lorem ipsum dolor sit {tag1(replaced)}, consectetur adipiscing elit. question as can see "tag2" has been replaced, want replace "tag1" know how can this? (in cases might this: {tag1({tag2({tag3()})})}) , on.) btw using preg_replace_callback, easier show preg_replace here site can test code: http://www.spaweditor.com/scripts/regex/index.php you need add curly braces character set. here's pattern used: /\{[a-za-z.,\(\)\{\}0-9]+\}/ and here result: "lorem ipsum dolor sit replaced, consectetur adipiscing elit."
Read more