Package g0301_0400.s0393_utf_8_validation

Class Solution

java.lang.Object
g0301_0400.s0393_utf_8_validation.Solution
public class Solution extends Object
393 - UTF-8 Validation.<p>Medium</p> <p>Given an integer array <code>data</code> representing the data, return whether it is a valid <strong>UTF-8</strong> encoding.</p> <p>A character in <strong>UTF8</strong> can be from <strong>1 to 4 bytes</strong> long, subjected to the following rules:</p> <ol> <li>For a <strong>1-byte</strong> character, the first bit is a <code>0</code>, followed by its Unicode code.</li> <li>For an <strong>n-bytes</strong> character, the first <code>n</code> bits are all one&rsquo;s, the <code>n + 1</code> bit is <code>0</code>, followed by <code>n - 1</code> bytes with the most significant <code>2</code> bits being <code>10</code>.</li> </ol> <p>This is how the UTF-8 encoding would work:</p> <pre><code> Char. number range | UTF-8 octet sequence (hexadecimal) | (binary) --------------------+--------------------------------------------- 0000 0000-0000 007F | 0xxxxxxx 0000 0080-0000 07FF | 110xxxxx 10xxxxxx 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx 0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx </code></pre> <p><strong>Note:</strong> The input is an array of integers. Only the <strong>least significant 8 bits</strong> of each integer is used to store the data. This means each integer represents only 1 byte of data.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> data = [197,130,1]</p> <p><strong>Output:</strong> true</p> <p><strong>Explanation:</strong> data represents the octet sequence: 11000101 10000010 00000001. It is a valid utf-8 encoding for a 2-bytes character followed by a 1-byte character.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> data = [235,140,4]</p> <p><strong>Output:</strong> false</p> <p><strong>Explanation:</strong> data represented the octet sequence: 11101011 10001100 00000100. The first 3 bits are all one&rsquo;s and the 4th bit is 0 means it is a 3-bytes character. The next byte is a continuation byte which starts with 10 and that&rsquo;s correct. But the second continuation byte does not start with 10, so it is invalid.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= data.length <= 2 * 10<sup>4</sup></code></li> <li><code>0 <= data[i] <= 255</code></li> </ul>

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • validUtf8

      public boolean validUtf8(int[] data)