300. Longest Increasing Subsequence

Given an integer array nums, return the length of the longest strictly increasing subsequence.

 

Example 1:

Input: nums = [10,9,2,5,3,7,101,18]
Output: 4
Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4.

Example 2:

Input: nums = [0,1,0,3,2,3]
Output: 4

Example 3:

Input: nums = [7,7,7,7,7,7,7]
Output: 1

 

 

public int lengthOfLIS(int[] nums) {
  int n = nums.length;
  int max_len = 0;
  int[] len = new int[n];
  for(int i = 0; i < n; i++) {
    len[i] = 1;
    for(int j = 0; j < i ; j++) {//对每一元素，都从第一个元素开始与它比较
      if(nums[i] > nums[j]) {
        if(len[i] < len[j] + 1)
          len[i] = len[j] + 1;
      }
    }
    if(max_len < len[i]){
      max_len = len[i];
    }
  }
  return max_len;
}