Help with error

#1

code: https://ide.codingblocks.com/s/467660

problem: https://leetcode.com/problems/remove-k-digits/

test case: num = 10200, k = 1 is failing

#2

hello @raghav007

please explain ur logic.
not getting from ur code

#3

I’m maintaining an increasing stack whenever the top element of stack is greater I’m popping till the top is smaller and also reducing k there is also a check if for example num is 123 then i removing k elements after this process is complete I convert the elements of stack into a string and I have also created a check for leading 0’s

#4

…

here after erasing the character from ans the idexing will change.
so cant do i++ everytime.

check this->


another way to avoid leading zero is to insert a char in stack only if ur stack in not empty

#5 
   return ans.empty() ? "0" : ans;

please explain this

#6

…

see we are never pushing leading zeros.
so for case like this -> 00000

our ans (string/stack) will remain empty hence we are checking it explicitly and returing 0

#7

if (ans.length() || c != '0') { ans.push_back(c);
what is the purpose of ans.length()

#8

…

when can we push the new char in the stack?
a) if we already have some non zero entries in stack. that why checking ans.length()(if greater than 0 )
b) if the current character is non zero . that is why c!=0
if any of them is true we can push

#9

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