leetcode 393. UTF-8 Validation | 393. UTF-8 编码验证（Java）

蔚落 2022-09-01 08:38 233阅读 0赞

## 题目 ##

[https://leetcode.com/problems/utf-8-validation/][https_leetcode.com_problems_utf-8-validation]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_1_color_FFFFFF_t_70]

## 题解 ##

分析完情况之后，这题就是 if-else 堆起来的而已。

class Solution { 
        public boolean validUtf8(int[] data) { 
            for (int i = 0; i < data.length; i++) { 
                int[] b = h2b(data[i]);
                int L = getLen(b);
                if (L == -1) return false;
                for (int j = 0; j < L - 1; j++) { 
                    if (i >= data.length - 1 || !check10(h2b(data[++i]))) return false;
                }
            }
            return true;
        }
    
        public boolean check10(int[] b) { 
            return b[0] == 1 && b[1] == 0;
        }
    
        public int getLen(int[] b) { 
            if (b[0] == 0) return 1;
            else if (b[0] == 1 && b[1] == 1 && b[2] == 0) return 2;
            else if (b[0] == 1 && b[1] == 1 && b[2] == 1 && b[3] == 0) return 3;
            else if (b[0] == 1 && b[1] == 1 && b[2] == 1 && b[3] == 1 && b[4] == 0) return 4;
            else return -1;
        }
    
        public int[] h2b(int i) {  // hex to bin
            int[] a = new int[8];
            int p = 0;
            while (i > 0) { 
                a[8 - p - 1] = i % 2;
                p++;
                i /= 2;
            }
            return a;
        }
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70]

[https_leetcode.com_problems_utf-8-validation]: https://leetcode.com/problems/utf-8-validation/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_1_color_FFFFFF_t_70]: /images/20220829/75b9d56c631e444d8699203f2c9fbd8b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70]: /images/20220829/a23d8fc6fc1d42848af357c356e2470e.png