673. Number of Longest Increasing Subsequence

673. Number of Longest Increasing Subsequence

• 题目描述：Given an unsorted array of integers, find the number of longest increasing subsequence.

• Example 1:

  Input: [1,3,5,4,7]Output: 2Explanation: The two longest increasing subsequence are [1, 3, 4, 7] and [1, 3, 5, 7].

• Example 2:

  Input: [2,2,2,2,2]Output: 5Explanation: The length of longest continuous increasing subsequence is 1, and there are 5 subsequences' length is 1, so output 5.

• 题目大意：给定一个未排序的int数组，找出最长子序列的个数

• 代码

  package DP;/*** @Author OovEver* @Date 2017/12/15 10:06*/public class LeetCode673 {  public int findNumberOfLIS(int[] nums) {      int n = nums.length;      int res = 0;      int max_len = 0;//        以nums[i]结尾的最长子序列的长度      int[] len = new int[n];//        以nums[i]结尾的最长子序列的个数      int[] count = new int[n];      for(int i=0;i<n;i++) {          len[i] = count[i] = 1;          for(int j=0;j<i;j++) {              if (nums[i] > nums[j]) {                  if(len[i]==len[j]+1) count[i] += count[j];                  if (len[i] < len[j] + 1) {                      len[i] = len[j] + 1;                      count[i] = count[j];                  }              }          }          if(max_len==len[i]) res += count[i];          if (max_len < len[i]) {              max_len = len[i];              res = count[i];          }      }      return res;  }}