How can I remove the segmentation error in the following code?

In the following code, I am getting the segmentation fault. Whenever the query type is 1, we have to push element into the stack, if it is 2 then we have to pop from stack, and if it is 3 then print the maximum value in the stack.

My guess is that the error is present somewhere in the switch case. However, I am unable to spot it. Please help.

#include<bits/stdc++.h>

using namespace std;

int maxinStack(stack<int> st){
    int max=st.top();
    for (int i=0;i<st.size();i++){
        if(st.top()>max){
            max=st.top();
        }
        st.pop();
    }
    return max;
}


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    stack<int> s;

    int querySize;
    cin >> querySize;

    vector<int> queryType(querySize);
    queue<int> queryData;

    for(int i=0;i<querySize;i++){
        cin>>queryType[i];
        if(queryType[i]==1){
            int x;
            cin >> x;
            queryData.push(x);
        }
    }

    /*for (int j=0;j<querySize;j++){
        cout << queryType.at(j)<<" ";
    }
    cout << endl;

    while(!queryData.empty()){
        cout << queryData.front()<<" ";
        queryData.pop();
    }
    cout << endl;
    */

    for (int j=0;j<querySize;j++){
        switch (queryType[j]){
            case 1:{
                int y=queryData.front();
                s.push(y);
                queryData.pop();
            }

            case 2: s.pop();

            case 3: cout << maxinStack(s)<<endl;
        }
    }
    return 0;
}