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array-get-all-combination.html
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array-get-all-combination.html
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<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
/**
* http://www.cnblogs.com/purediy/archive/2012/12/02/2798454.html
* 获得指定数组的所有组合
* 一维数组
*/
function arrayCombine(targetArr) {
if(!targetArr || !targetArr.length) {
return [];
}
var len = targetArr.length;
var resultArrs = [];
// 所有组合
for(var n = 1; n < len; n++) {
var flagArrs = getFlagArrs(len, n);
while(flagArrs.length) {
var flagArr = flagArrs.shift();
var combArr = [];
for(var i = 0; i < len; i++) {
flagArr[i] && combArr.push(targetArr[i]);
}
resultArrs.push(combArr);
}
}
return resultArrs;
}
/**
* 获得从m中取n的所有组合
*/
function getFlagArrs(m, n) {
if(!n || n < 1) {
return [];
}
var resultArrs = [],
flagArr = [],
isEnd = false,
leftCnt;
for (var i = 0; i < m; i++) {
flagArr[i] = i < n ? 1 : 0;
}
resultArrs.push(flagArr.concat());
while (!isEnd) {
leftCnt = 0;
for (var i = 0; i < m - 1; i++) {
if (flagArr[i] == 1 && flagArr[i+1] == 0) {
for(var j = 0; j < i; j++) {
flagArr[j] = j < leftCnt ? 1 : 0;
}
flagArr[i] = 0;
flagArr[i+1] = 1;
var aTmp = flagArr.concat();
resultArrs.push(aTmp);
if(aTmp.slice(-n).join("").indexOf('0') == -1) {
isEnd = true;
}
break;
}
flagArr[i] == 1 && leftCnt++;
}
}
return resultArrs;
}
function getArr(n){
var arr = [];
for(var i=1; i<=n; i++){
arr.push(i);
}
return arr;
}
//demo
var arr = getArr(5);
console.log(arr); //Array [ 1, 2, 3 ]
var newArr = arrayCombine(arr);
console.log(newArr.toString()); // "1,2,3, 1,2,1, 3,2,3" ? 212, 131,
document.write(newArr);
// 1,2,3,4,5,
// 1,2,1,3,2,
// 3,1,4,2,4,
// 3,4,1,5,2,
// 5,3,5,4,5,
// 1,2,3,1,2,
// 4,1,3,4,2,
// 3,4,1,2,5,
// 1,3,5,2,3,
// 5,1,4,5,2,
// 4,5,3,4,5,
// 1,2,3,4,1,
// 2,3,5,1,2,
// 4,5,1,3,4,
// 5,2,3,4,5
</script>
</body>
</html>