Seg fault in this code of leetcode

#1

string removeDuplicateLetters(string s) {

    int arr[126]={0};
    int n=s.length();
    for(int i=0;i<n;i++)
    {
        arr[s[i]]+=1;
    }
    stack<char>s1;
    int i=1;
    s1.push(s[0]);
    while(i<s.length())
    {
        char ch=s[i];
        while(s1.top()>ch and !s1.empty())
        {
            if( arr[s1.top()]>1)
            {
                s1.pop();
            }
        }
        s1.push(s[i]);
        i++;
    }
    string ans="";
    while(!s1.empty())
    {
        ans=s1.top()+ans;
        s1.pop();
    }
    return ans;
}
#2

Hello @singhsimran567 could you please share the question link.

#3
#4

@singhsimran567 the problem is in this:
while(s1.top()>ch and !s1.empty())
{
if( arr[s1.top()]>1)
{
s1.pop();
}
}
when you will go inside this loop :
then there is no condition which will stop this.
That’s why you are getting this error.
like: “bcabc”
after bc when a will come that while condition will become true and you will then not be able to come out of it.
Happy Learning!!

1 Like
#5

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