Cod sursă (job #545034)

#include <bits/stdc++.h>
using namespace std;
ifstream f ("reactivi.in");
ofstream g ("reactivi.out");
int n,i,j,p;
struct interval
{
    int s,d;
}v[251],a[8001];
bool cmp(interval x, interval y )
{
        return x.s < y.s;
}
int main()
{
    f >> n;
    for (i = 1; i <= n; i++ )
        f >> a[i].s >> a[i].d;
    sort(a+1,a+n+1,cmp);
    v[1].s = a[1].s;
    v[1].d = a[1].d;
    p = 1;
    for ( i = 2; i <= n; i++ )
        if ( a[i].s >= v[p].s && a[i].s <= v[p].d )
        {
            v[p].s = a[i].s;
            if ( a[i].d < v[p].d )
                v[p].d = a[i].d;
        }
        else
        {
            p++;
            v[p].s = a[i].s;
            v[p].d = a[i].d;
        }
    g << p;
    //for (i = 1; i <= n; i++ )
        //g << a[i] << " " << b[i] << "\n";

    return 0;
}