From 11e22a40d88086a782a4af1b6a964305f391dafc Mon Sep 17 00:00:00 2001 From: Deven <63876261+devenperez@users.noreply.github.com> Date: Thu, 14 Jul 2022 17:45:10 -0400 Subject: [PATCH] Create README - LeetHub --- 8-string-to-integer-atoi/README.md | 74 ++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 8-string-to-integer-atoi/README.md diff --git a/8-string-to-integer-atoi/README.md b/8-string-to-integer-atoi/README.md new file mode 100644 index 0000000..3866ace --- /dev/null +++ b/8-string-to-integer-atoi/README.md @@ -0,0 +1,74 @@ +

8. String to Integer (atoi)

Medium

Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++'s atoi function).

+ +

The algorithm for myAtoi(string s) is as follows:

+ +
    +
  1. Read in and ignore any leading whitespace.
    2. +
  2. Check if the next character (if not already at the end of the string) is '-' or '+'. 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.
    3. +
  3. 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.
    4. +
  4. Convert these digits into an integer (i.e. "123" -> 123, "0032" -> 32). If no digits were read, then the integer is 0. Change the sign as necessary (from step 2).
    5. +
  5. If the integer is out of the 32-bit signed integer range [-231, 231 - 1], then clamp the integer so that it remains in the range. Specifically, integers less than -231 should be clamped to -231, and integers greater than 231 - 1 should be clamped to 231 - 1.
    6. +
  6. Return the integer as the final result.
    7. +
+ +

Note:

+ + + +

 

+

Example 1:

+ +
Input: s = "42"
+Output: 42
+Explanation: The underlined characters are what is read in, the caret is the current reader position.
+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)
+           ^
+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:
+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.
+Since -42 is in the range [-231, 231 - 1], the final result is -42.
+
+ +

Example 3:

+ +
Input: s = "4193 with words"
+Output: 4193
+Explanation:
+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.
+Since 4193 is in the range [-231, 231 - 1], the final result is 4193.
+
+ +

 

+

Constraints:

+ + +
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