57_和为s的连续正数序列

57_和为s的连续正数序列

 

package 数组;
/**
 * 题意：暗示了数据是升序的
 * https://leetcode-cn.com/problems/he-wei-sde-lian-xu-zheng-shu-xu-lie-lcof/
 */
import java.util.ArrayList;
import java.util.List;

public class _57_和为s的连续正数序列 {
    public int[][] findContinuousSequence(int target) {
        List<int[]> vec = new ArrayList<int[]>();
        int left = 1, right = 2;
        while(left < right) {
            //求和公式
            int sum = (left + right) * (right - left + 1) / 2;
            if (sum == target) {
                int[] res = new int[right - left + 1];
                for (int i = left; i <= right; ++i) {
                    res[i - left] = i;
                }
                vec.add(res);
                left++;    //找到之后，左边指针往前挪动，(微调)
            } else if (sum < target) {
                right++;
            } else {
                left++;
            }
        }
        return vec.toArray(new int[vec.size()][]);
    }
}