Coder-Strike 2014

const int MAXN = 310000;struct Node{    int n, num;    int operator, int> mp;        FE(i, 1, n) ipt[i].n = i;        FE(i, 1, n) ipt[i].num = 0;        REP(i, n)        {            RI(a); ipt[a].num++; cnt[a]++;            RI(b); ipt[b].num++; cnt[b]++;            if (a > b) swap(a, b);            mp[MP(a, b)]++;        }        sort(ipt + 1, ipt + n + 1);        LL ans = 0;        FE(i, 1, n)        {            int ind = lower_bound(ipt + i + 1, ipt + n + 1, k - ipt[i].num, cmp) - ipt;            ans += n - ind + 1;        }        FC(it, mp)        {            a = (it->first).first; b = (it->first).second;            if (cnt[a] + cnt[b] >= k && cnt[a] + cnt[b] - it->second   <br>  <br>  <p></p>