滑动窗口-和为S的连续正数序列

package slidewindow;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class ContinuousSequence {

    private static List<String> findSequence(int s) {
        int[] nums = new int[s];
        for (int i = 0; i < s; i++) {
            nums[i] = i + 1;
        }
        Set<Integer> window = new HashSet<>();
        // 初始化游标
        int left = 0, right = 0;
        List<String> res = new ArrayList<>();
        while (right < nums.length) {
            window.add(nums[right]);
            right++;
            while (sumWindow(window) == s) {
                res.add(strWindow(window));
                window.remove(nums[left]);
                left++;
            }
        }
        return res;
    }

    private static int sumWindow(Set<Integer> window) {
        int sum = 0;
        for (Integer o : window) {
            sum += o;
        }
        return sum;
    }

    private static String strWindow(Set<Integer> window) {
        StringBuilder str = new StringBuilder();
        for (Integer o : window) {
            str.append(o);
        }
        return str.toString();
    }

    public static void main(String[] args) {
        List<String> a = findSequence(3);
    }
    
}