JavaScript实现三阶幻方算法谜题解答_javascript技巧

function getPermutation(arr) {
if (arr.length == 1) {
return [arr];
}

var permutation = [];
for (var i=0; i var firstEle = arr[i];
var arrClone = arr.slice(0);
arrClone.splice(i, 1);
var childPermutation = getPermutation(arrClone);
for (var j=0; j childPermutation[j].unshift(firstEle);
}
permutation = permutation.concat(childPermutation);
}
return permutation;
}

function validateCandidate(candidate) {
var sum = candidate[0] + candidate[1] + candidate[2];
for (var i=0; i<3; i++) {
if (!(sumOfLine(candidate,i)==sum && sumOfColumn(candidate,i)==sum)) {
return false;
}
}
if (sumOfDiagonal(candidate,true)==sum && sumOfDiagonal(candidate,false)==sum) {
return true;
}
return false;
}
function sumOfLine(candidate, line) {
return candidate[line*3] + candidate[line*3+1] + candidate[line*3+2];
}
function sumOfColumn(candidate, col) {
return candidate[col] + candidate[col+3] + candidate[col+6];
}
function sumOfDiagonal(candidate, isForwardSlash) {
return isForwardSlash ? candidate[2]+candidate[4]+candidate[6] : candidate[0]+candidate[4]+candidate[8];
}

var permutation = getPermutation([1,2,3,4,5,6,7,8,9]);
var candidate;
for (var i=0; i candidate = permutation[i];
if (validateCandidate(candidate)) {
break;
} else {
candidate = null;
}
}
if (candidate) {
console.log(candidate);
} else {
console.log('No valid result found');
}