菜鸡单调栈

#include <bits/stdc++.h>
#include<stack>
using namespace std;
typedef long long ll;
const int N=1e5+5;
int s1[N],s2[N];
int ans;
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int n;
   s1[0]=0;
   s2[0]=0;
    while(cin>>n){
        stack<int> st1;
        stack<int> st2;
        for(int i=1;i<=n;i++)
            cin>>s1[i];
        for(int i=1;i<=n;i++)
            cin>>s2[i];
        st1.push(s1[1]);
        st2.push(s2[1]);
        for(int i=2;i<=n;i++)
        {
            while(!st1.empty()&&st1.top()>s1[i]){
                st1.pop();
            }
            st1.push(s1[i]);
            while(!st2.empty()&&st2.top()>s2[i]){
                st2.pop();
            }
            st2.push(s2[i]);
            if(st1.size()!=st2.size())
            {
                cout<<i-1<<endl;
                break;
            }

            if(i==n)
                cout<<n<<endl;
        }
    }
    return 0;
}