g0001_0100.s0008_string_to_integer_atoi.Solution

public class Solution extends Object

8 - String to Integer (atoi).Medium Implement the <code>myAtoi(string s)</code> function, which converts a string to a 32-bit signed integer (similar to C/C++’s <code>atoi</code> function). The algorithm for <code>myAtoi(string s)</code> is as follows: <ol> <li>Read in and ignore any leading whitespace.</li> <li>Check if the next character (if not already at the end of the string) is <code>'-'</code> or <code>'+'</code>. Read this character in if it is either. This determines if the final result is negative or positive respectively. Assume the result is positive if neither is present.</li> <li>Read in next the characters until the next non-digit character or the end of the input is reached. The rest of the string is ignored.</li> <li>Convert these digits into an integer (i.e. <code>"123" -> 123</code>, <code>"0032" -> 32</code>). If no digits were read, then the integer is <code>0</code>. Change the sign as necessary (from step 2).</li> <li>If the integer is out of the 32-bit signed integer range <code>[-231, 231 - 1]</code>, then clamp the integer so that it remains in the range. Specifically, integers less than <code>-231</code> should be clamped to <code>-231</code>, and integers greater than <code>231 - 1</code> should be clamped to <code>231 - 1</code>.</li> <li>Return the integer as the final result.</li> </ol> Note: <ul> <li>Only the space character <code>' '</code> is considered a whitespace character.</li> <li>Do not ignore any characters other than the leading whitespace or the rest of the string after the digits.</li> </ul> Example 1: Input: s = “42” Output: 42 Explanation: The underlined characters are what is read in, the caret is the current reader position. <pre><code> Step 1: "42" (no characters read because there is no leading whitespace) ^ Step 2: "42" (no characters read because there is neither a '-' nor '+') ^ Step 3: "42" ("42" is read in) ^ </code></pre> The parsed integer is 42. Since 42 is in the range [-231, 231 - 1], the final result is 42. Example 2: Input: s = " -42" Output: -42 Explanation: <pre><code> Step 1: " -42" (leading whitespace is read and ignored) ^ Step 2: " -42" ('-' is read, so the result should be negative) ^ Step 3: " -42" ("42" is read in) ^ The parsed integer is -42. </code></pre> Since -42 is in the range [-231, 231 - 1], the final result is -42. Example 3: Input: s = “4193 with words” Output: 4193 Explanation: <pre><code> Step 1: "4193 with words" (no characters read because there is no leading whitespace) ^ Step 2: "4193 with words" (no characters read because there is neither a '-' nor '+') ^ Step 3: "4193 with words" ("4193" is read in; reading stops because the next character is a non-digit) ^ The parsed integer is 4193. </code></pre> Since 4193 is in the range [-231, 231 - 1], the final result is 4193. Example 4: Input: s = “words and 987” Output: 0 Explanation: <pre><code> Step 1: "words and 987" (no characters read because there is no leading whitespace) ^ Step 2: "words and 987" (no characters read because there is neither a '-' nor '+') ^ Step 3: "words and 987" (reading stops immediately because there is a non-digit 'w') ^ The parsed integer is 0 because no digits were read. </code></pre> Since 0 is in the range [-231, 231 - 1], the final result is 0. Example 5: Input: s = “-91283472332” Output: -2147483648 Explanation: <pre><code> Step 1: "-91283472332" (no characters read because there is no leading whitespace) ^ Step 2: "-91283472332" ('-' is read, so the result should be negative) ^ Step 3: "-91283472332" ("91283472332" is read in) ^ The parsed integer is -91283472332. </code></pre> Since -91283472332 is less than the lower bound of the range [-231, 231 - 1], the final result is clamped to -231 = -2147483648. Constraints: <ul> <li><code>0 <= s.length <= 200</code></li> <li><code>s</code> consists of English letters (lower-case and upper-case), digits (<code>0-9</code>), <code>' '</code>, <code>'+'</code>, <code>'-'</code>, and <code>'.'</code>.</li> </ul>

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Solution()
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Method

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int

myAtoi(String str)

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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- Solution
  
  public Solution()
Method Details
- myAtoi
  
  public int myAtoi(String str)

Class Solution

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Solution

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myAtoi