300. Longest Increasing Subsequence(DP)

 1 //Old
 2 class Solution {
 3     public int lengthOfLIS(int[] nums) {
 4         int max = 0;
 5         int n = nums.length;
 6         if(n == 0) return 0;
 7         int[] res = new int[n];
 8         for(int i = 0; i < n; i++) {
 9             res[i] = 1;
10             for(int j = 0; j < i; j++) { 
11                 if(nums[j] < nums[i]) {
12                     res[i] = Math.max(res[i], res[j] + 1);
13                 }
14             }
15             max = res[i] > max ? res[i] : max; //放到外面的循环 方便点
16         }
17         return max;
18     }
19 }

 1 //New
 2 
 3 class Solution {
 4     public int lengthOfLIS(int[] nums) {
 5         int n = nums.length;
 6         int[] dp = new int[n];
 7         int len = 0;
 8         for(int num : nums) {
 9             int i = Arrays.binarySearch(dp, 0, len, num);
10             if(i < 0) {
11                 i = -(i + 1);
12             }
13             dp[i] = num;
14             if(i == len) len++;
15         }
16         return len;
17     }
18 
19 }