[Leetcode] [Java] String to Integer (atoi)

Topic:

Implement atoi to convert a string to an integer.

Hint: Carefully consider all possible input cases. If you want a challenge, please don't see below and ask yourself what is the possible input cases.

Notes: It is intended for the problem to be specified vaguely (ie, no given input specs). You is responsible to gather all the input requirements up front.

Test instructions

Implements Atoi, converting a string to an integer.

Take care to consider all possible scenarios.

Algorithm Analysis:

1. Remove the extra space characters first, starting with the first non-whitespace character.

2. Read the numbers sequentially and end if the following three cases occur:

2.1 Exception characters appear (exception characters skip).

2.2 Digits out of bounds (returns the nearest integer).

2.3 End of string

Look directly at the code, no difficulty.

AC Code:

public class Solution {public    int myatoi (String str)    {        int max = Integer.max_value;        int min =-integer.min_value;        Long result = 0;        str = Str.trim ();        int len = Str.length ();        if (Len < 1)            return 0;        int start = 0;        Boolean neg = false;//indicates positive and negative         if (str.charat (start) = = '-' | | | Str.charat (START) = = ' + ')         {            if (Str.charat (star t) = = '-')                neg = true;            start++;        }         for (int i = start; i < Len; i++)         {            char ch = str.charat (i);             if (Ch < ' 0 ' | | ch > ' 9 ') break                ;            result = Ten * result + (CH-' 0 ');            if (!neg && result > Max)//exceeds the boundary, returns the boundary value directly to                Max;            if (Neg &&-result < min)                return min;         }        if (neg)            result =-result;         return (int) result;}    }

Copyright NOTICE: This article is the original article of Bo Master, reprint annotated source

[Leetcode] [Java] String to Integer (atoi)