714A - Meeting of Old Friends - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
const ll MAXN = 2e5+100;
#define io ios::sync_with_stdio(false),cin.tie(NULL),cout.tie(NULL);
#define ll long long
#define push(a) push_back(a)
#define pop(a) pop_back(a)
#define all(a) (a).begin(), (a).end()
#define sz(a) (a).size()
#define fork(i,a,n) for(ll i=a; i<n; i++)
#define kfor(i,a,n) for(ll i=a; i>=n; i--)
#define input(v,n) for(ll i=0; i<n; i++) cin>>v[i];
#define max(x) *max_element(all(x))
#define min(x) *min_element(all(x))
#define sum(x)  accumulate(all(x), 0LL)
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
void ok(bool foo){foo?yes:no;}
//cout << fixed << setprecision(n) <<  << endl;

int main(){
    io
    
    ll l1, r1, l2, r2, k, c1, c2, c=0;
    cin >> l1 >> r1 >> l2 >> r2 >> k;
    
    if(l1 <= l2){
        if(r1 >= r2) {
            if(k >= l2 and k <= r2) {
                c = r2 - l2;    
            }
            else {
                c = r2 - l2 + 1;
            }
        }
        else if(r1 < l2) {
        }
        else if(k <= r1 and k >= l2) {
            c = r1 - l2;
        }
        else {
            c = r1 - l2 + 1;
        }
    }
    else {
        if(r2 >= r1) {
            if(k >= l1 and k <= r1) {
                c = r1 - l1;    
            }
            else {
                c = r1 - l1 + 1;
            }
        }
        else if(r2 < l1) {
        }
        else if(k <= r2 and k >= l1) {
            c = r2 - l1;
        }
        else {
            c = r2 - l1 + 1;
        }
    }
    
    cout << c << endl;
    
    return 0;
}