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Today's topic:
Please use the algorithm to achieve, from the given unordered, non-repetitive array data, take out n numbers, and make the sum of them sum. And give the time/space complexity of the algorithm. (There is no need to find all the solutions, just find one)
answer:
/**
*
* 解题思路：从array中取出n个数全排列，在取的同时判断是否符合条件，为了不影响后续排列，每次递归完成，将当前的数组添加到正在排序的array中
* 时间复杂度O(n)
* 空间复杂度O(n)
* @param {Array} array 需要判断的数组
* @param {number} n 取出n个数
* @param {number} sum 和为sum的值
* @param {array} temp 输出和为sum的数组
*/
function getAllCombin(array, n, sum, temp) {
if (temp.length === n) {
if (temp.reduce((t, c) => t + c) === sum) {
return temp;
}
return false;
}
for (let i = 0; i < array.length; i++) {
const current = array.shift();
temp.push(current);
const result = getAllCombin(array, n, sum, temp);
if (result) {
return result;
}
temp.pop();
array.push(current);
}
}
const arr = [1, 5, 6, 2, 4, 3];
console.log(getAllCombin(arr, 3, 10, []));
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