Amazon interview question | String to Integer (atoi) | leetcode 8

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#leetcode #python

[engineersvlog]

This code is not working when index [0] is negative sign . Because we run our loop from index 1 . And that time in our out only - is stored. So don't able to all the string to integer

[avnishgupta]

what if input is " - 42" and " 90 09"?

[davidraygoza]

Here is complete code (I'm sure you can make some optimizations):
class Solution(object):
def myAtoi(self, s):
upperBound = 2 ** 31
lowerBound = upperBound * (-1)
integerCounter = 0
tenCounter = 1
idx = 0
digitStack = []
length = len(s)
s = s.strip()
isNeg = False

if len(s) == 0:
return 0

if s[0] == '+':
isNeg = False
idx = 1
elif s[0] == '-':
isNeg = True
idx = 1
elif not s[0].isnumeric():
return 0

if idx >= length or not s[idx].isnumeric():
return 0

while idx < len(s):
if s[idx].isnumeric():
digitStack.append(ord(s[idx]) - 48)
idx += 1
else:
idx = length

while len(digitStack) > 0:
poppedVal = digitStack[-1]
digitStack.pop()
integerCounter += poppedVal * tenCounter
tenCounter *= 10


if isNeg:
integerCounter *= -1

if integerCounter > upperBound-1:
return upperBound - 1
elif integerCounter < lowerBound+1:
return lowerBound
else:
return integerCounter

[ajaykotian]

Thank you for taking the time to make this video. You did an awesome job of explaining it.

[vee-obsidian]

thanks for these videos - curious, wouldn't casting integer values be sufficient using int("1") instead of retrieving ascii value thru ord calls? thanks

[shashwatshekhar]

Best solution out there on youtube - Clear and concise. Well done!

[alibabascience]

Coding : By AGHOUJDAM Ettijani, with C langaue :
// function to convet asccii caracter to integer number : this function take a string
// of caracters and return value or 0 in error case
#include<stdio.h>
#include<stdlib.h>


int ft_atoi(char *str) // function prototype
{
int i; // declaration of increment index in integer type
int nbr; // declaration of number in i store my result of convert operation
int sign; // declaration signed flag if the user input the signed string

nbr = 0; // initialization
i = 0; // initialization

sign = 1; // initialization
if (str[0] == '-') // we tcheck if the first string is minus
{
sign = -1; // convert the signe to negative value to multiply it on return value
i++; // we increment to second caracter
}
while(str[i] != '\0')
{
if ((str[i] - '0') > 9) // we tchecking if the caracter indexing minus zero carter is > 9 we return 0 because the result is out of arangement 0 to 9
return (nbr * sign);
nbr = (nbr * 10) + (str[i] - 48);//or nbr = nbr * 10 + str[i] - '0'
i++;
}
return (nbr * sign);
}

int main(int argc, char **argv) {

if (argc != 2)
return (1);
printf("%d\n", ft_atoi(argv[1]));
printf("%d", atoi(argv[1]));

return 0;
}

[gouravmitra]

Awesome explanation.Shouldnot isnumeric on line 14 should be isnumeric() with braces-just a typo but thought will point out

[xiubinzheng]

great video man, what is the tool that you use to draw with this video of the coding diagram?

[ShubhamPatil-bvmk]

not working for " -42" why?

[Plutonium_]

Why are not You continuing this kind of learning and helpful video Bro???

[suryaprakashs]

Red color part is not visible can you use some other color's instead of red

[divyanshukumar]

Keep on going
These videos really help us
:)

[vedantshirpurkar]

Hey can you make a playlistfor Goldman Sachs Placement coding ques and for TCS codevita too

[utkarshsharma]

Indentation of the for loop is wrong. The for loop is not inside the else condition.

[jugh]

but y cant we directly use
if (l.isdigit()):
l=int(l)
instead of using ord to make things difficult for us?

[vipingautam]

will this work for " -41 "

[prachimutha]

when str[]=='+' then negative is false. why?

[maheshjindal]

Pehle toh phir bhi samjh aa rha tha, code dekha tabh toh bilkul hi upar se a gaya, not understood (as you wrote in python)

[missimpersia]

It shows str object has no attribute isnumeric