View Code of Problem 6

#include <iostream>
#include <sstream>
#include <stdio.h>
#include <string>
#include <math.h>
#include <algorithm>
#include <stdlib.h>
#include <stack>
#include <map>
#include <set>
#include <queue>
using namespace std;

int main()
    {
        #ifdef  ONLINE_JUDGE
        #else
        freopen("1.txt","r",stdin);
        #endif
        int k;
        cin>>k;
        while(k--)
        {

            int n;
            cin>>n;
            int temp1,temp2;
            n--;
            cin>>temp1>>temp2;
            if(temp1!=0||temp2-temp1!=1) {cout<<"NO";continue;}
            bool flag=1;
            while(n--)
            {
                int a,b;
                cin>>a>>b;
                if(a!=temp2) {flag=0;break;}
                if(b-a!=1) {flag=0;break;}
                temp1=a;
                temp2=b;
            }
            if(flag==1) {cout<<"YES";}
            else {cout<<"NO";}
            cout<<endl;
        }

    }