最长上升子序列

Posted 2022-12-09 Alice_yufeng

class Solution 
    public int lengthOfLIS(int[] nums) 
        int len = 1, n = nums.length;
        if (n == 0) 
            return 0;
        
        int[] d = new int[n + 1];
        d[len] = nums[0];
        for (int i = 1; i < n; ++i) 
            if (nums[i] > d[len]) 
                d[++len] = nums[i];
             else 
                int l = 1, r = len, pos = 0; // 如果找不到说明所有的数都比 nums[i] 大，此时要更新 d[1]，所以这里将 pos 设为 0
                while (l <= r) 
                    int mid = (l + r) >> 1;
                    if (d[mid] < nums[i]) 
                        pos = mid;
                        l = mid + 1;
                     else 
                        r = mid - 1;
                    
                
                d[pos + 1] = nums[i];
            
        
        return len;