1008B - Turn the Rectangles - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
#define int long long

bool isPrime(int n)
{
  for (int i = 2; i * i <= n; ++i)
  {
    if (n % i == 0)
    {
      return false;
    }
  }
  return true;
}
int mod = 1e9 + 7;
int power(int x, int y)
{
  int z = 1;

  x = x % mod;
  while (y > 0)
  {
    if (y & 1)
      z = (z * x) % mod;
    y = y >> 1;
    x = (x * x) % mod;
  }
  return z;
}
int lcm(int a, int b)
{
  return (a * b) / __gcd(a, b);
}

bool so(const pair<int, int> &a,
        const pair<int, int> &b)
{
  if (a.first != b.first)
    return (a.first < b.first);
  else
    return (a.second > b.second);
}

int getsum(int n)
{
  int sum = 0;
  while (n != 0)
  {
    sum = sum + n % 10;
    n = n / 10;
  }
  return sum;
}

void sort(map<int, int> &M) // sort map by value
{

  // Declare a multimap
  multimap<int, int> MM;

  // Insert every (key-value) pairs from
  // map M to multimap MM as (value-key)
  // pairs
  for (auto &it : M)
  {
    MM.insert({it.second, it.first});
  }
}

signed main()
{
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  // int t;
  // cin >> t;
  // while (t--)
  // {
     int n;
     cin>>n;
     vector<int> v1;
     vector<int> v2;
     for(int i=0;i<n;i++){
      int w,h;
      cin>>w>>h;
      v1.push_back(max(w,h));
      v2.push_back(min(w,h));
     }
     int prev=v1[0];
     bool f=true;
     for(int i=0;i<n-1;i++){
      if(prev<v2[i+1]){
        f=false;
        break;
      }
      else{
        if(prev>=v1[i+1]){
          prev=v1[i+1];
        }
        else{
          prev=v2[i+1];
        }
      }
     }
     if(f){
      cout<<"YES"<<endl;
     }
     else{
      cout<<"NO"<<endl;
     }


  // }
}