[Lintcode]Longest Increasing Continuous Subsequence

Give an integer array，find the longest increasing continuous subsequence in this array.

An increasing continuous subsequence:

• Can be from right to left or from left to right.

• Indices of the integers in the subsequence should be continuous.

Example

For [5, 4, 2, 1, 3], the LICS is [5, 4, 2, 1], return 4.

For [5, 1, 2, 3, 4], the LICS is [1, 2, 3, 4], return 4.

设置flag储存当前升序或者降序。当升序序列改为降序时更新最大长度并初始化maxLen。注意此时maxLen长度为2.

题目要求：O(n) time and O(1) extra space.

public class Solution {    /**     * @param A an array of Integer     * @return  an integer     */    public int longestIncreasingContinuousSubsequence(int[] A) {                if(A.length == 0) return 0;                int maxLen = 1;        int res = 0;        int incr = 0;                for(int i = 1; i < A.length; i++) {            if(A[i] > A[i - 1]) {                if(incr == 1 || incr == 0) {                    maxLen ++;                    incr = 1;                }                else {                    res = Math.max(res, maxLen);                    maxLen = 2;                         incr = 1;                }            }            if(A[i] < A[i - 1]) {                if(incr == -1 || incr == 0) {                    maxLen ++;                    incr = -1;                }                else {                    res = Math.max(res, maxLen);                    maxLen = 2;                    incr = -1;                }            }        }                return Math.max(res, maxLen);    }}