8. String to Integer (atoi)
Problem's Link
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Mean:
给你一个字符串，让你将其转换为数字.
analyse:
注意细节，坑点有点多.
Time complexity: O(N)
view code
class
Solution
{
public :
int myAtoi( string str)
{
int ret = 0 , sign = 1 , i = str . find_first_not_of( ' ' ), base = INT_MAX / 10;
if ( str [ i ] == '+' || str [ i ] == '-') sign = str [ i ++ ] == '+' ?: - 1;
while ( isdigit( str [ i ]))
{
if ( ret > base || ( ret == base && str [ i ] - '0' > 7))
return sign > 0 ? INT_MAX : INT_MIN;
ret = 10 * ret + ( str [ i ++ ] - '0');
}
return sign * ret;
}
};
{
public :
int myAtoi( string str)
{
int ret = 0 , sign = 1 , i = str . find_first_not_of( ' ' ), base = INT_MAX / 10;
if ( str [ i ] == '+' || str [ i ] == '-') sign = str [ i ++ ] == '+' ?: - 1;
while ( isdigit( str [ i ]))
{
if ( ret > base || ( ret == base && str [ i ] - '0' > 7))
return sign > 0 ? INT_MAX : INT_MIN;
ret = 10 * ret + ( str [ i ++ ] - '0');
}
return sign * ret;
}
};
