1920A - Satisfying Constraints - CodeForces Solution

#include <bits/stdc++.h>

using namespace std;

int main()
{
    int t;

    cin >> t;

    while(t--)
    {
        int n;

        cin >> n;

        int one=0,two=1000000001;
        vector<int> three;

        int first,second;
        for(int i=0;i<n;i++)
        {
            cin >> first >> second;

            if(first==1)
            {
                one=max(one,second);
            }
            else if(first==2)
            {
                two=min(two,second);
            }
            else
            {
                three.push_back(second);
            }
        }

        //cout << one << ' ' << two << endl;
        if(one>two)
        {
            cout << 0 << endl;
            continue;
        }
        int res=two-one+1;
        //cout << res << ' ';
        for(int num:three)
            if(num>=one && num<=two)
                res--;

        cout << res << endl;
    }

    return 0;
}