Submission #507384

#	Time	Username	Problem	Language	Result	Execution time	Memory
507384		Aldas25	Palembang Bridges (APIO15_bridge)	C++14	100 / 100	432 ms	40084 KiB

bridge

#include <bits/stdc++.h>

using namespace std;

#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr)
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define REP(n) FOR(O, 1, (n))
#define pb push_back
#define f first
#define s second
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vii;

const int MAXN = 500100;
const ll INF = (ll)1e17;

struct median {
    ll sum1 = 0, sum2 = 0;
    priority_queue<ll> q1;
    priority_queue<ll, vl, greater<ll>> q2;

    void clear () {
        sum1 = sum2 = 0;
        while (!q1.empty()) {q1.pop();}
        while (!q2.empty()) {q2.pop();}
    }

    void ins (ll s, ll t) {
        if (q1.empty()) {
            q1.push(s); sum1 += s;
            q2.push(t); sum2 += t;
            return;
        }

        ll a = q1.top(); q1.pop(); sum1 -= a;
        ll b = q2.top(); q2.pop(); sum2 -= b;

        if (b < s) swap(b, s);
        if (t < a) swap(a, t);

        q1.push(a); sum1 += a;
        q1.push(s); sum1 += s;
        q2.push(b); sum2 += b;
        q2.push(t); sum2 += t;
    }

    ll get () {
        return sum2 - sum1;
    }

};

int k, nn, n;
ll s[MAXN], t[MAXN];
vl pts;
set<ll> tmp;
map<ll, int> toId;
ll ans;
vector<pair<ll, int>> sortedS, sortedT, sortedST;

ll closed[MAXN], notOpened[MAXN];

void preCalc () {

    /// compression of points
    FOR(i, 1, n) {
        tmp.insert(s[i]);
        tmp.insert(t[i]);
    }

    ll id = 0;
    for (ll x : tmp) {
        pts.pb(x);
        toId[x] = id;
        id++;
    }

    /// sortedS and sortedT
    FOR(i, 1, n) {
        sortedS.pb({s[i], i});
        sortedT.pb({t[i], i});
        sortedST.pb({s[i] + t[i], i});
    }
    sort(sortedS.begin(), sortedS.end());
    sort(sortedT.begin(), sortedT.end());
    sort(sortedST.begin(), sortedST.end());

    /// closed and notOpen calc
    notOpened[0] = n;

    FOR(i, 1, n) {
        notOpened[toId[s[i]]]--;
        closed[toId[t[i]]]++;
    }

    FOR(i, 1, (int)pts.size()-1) {
        notOpened[i] += notOpened[i-1];
        closed[i] += closed[i-1];
    }
}

ll solve1 () {
    //ll curMin = INF;
    ll cur = 0;

    int ch = 0;
    FOR(i, 0, (int)pts.size()-1) {
        if (closed[i] >= notOpened[i]) {
            ch = pts[i];
            break;
        }
    }

    FOR(i, 1, n) {
        cur += abs(s[i] - ch) + abs(t[i] - ch);
    }

    //ans += cur;
    //cout << ans << "\n";
    return ans+cur;
}

ll pref[MAXN], suf[MAXN];

ll solve2 () {
    ll cur = 0;
    ll minCur = INF;

    median m;
    m.clear();

    FOR(i, 0, n-1) {
        int id = sortedST[i].s;
        m.ins(s[id], t[id]);
        pref[i] = m.get();
       // cout << " i = " << i << "  id = " << id << " pref i = " << pref[i] << endl;
    }
    m.clear();

    for (int i = n-1; i >= 0; i--) {
        int id = sortedST[i].s;
        m.ins(s[id], t[id]);
        suf[i] = m.get();
        //cout << " i = " << i << "  id = " << id << " suf i = " << suf[i] << endl;
    }

    minCur = suf[0];
    FOR(i, 0, n-2) {
        minCur = min(minCur, pref[i] + suf[i+1]);
    }

    return ans+minCur;
}

int main()
{
    FAST_IO;

    cin >> k >> nn;

    FOR(i, 1, nn) {
        char pp, qq;
        ll ss, tt;
        cin >> pp >> ss >> qq >> tt;
        if (pp == qq) {
            ans += abs(ss-tt);
        } else {
            n++;
            ans++;
            //ans += abs(ss-tt);
            s[n] = min(ss,tt);
            t[n] = max(ss,tt);
        }
    }
    //cout << " ans = " << ans << endl;

    preCalc();

    if (k == 1 || (int)pts.size() == 1) {
        cout << solve1() << "\n";
        return 0;
    } else {
        ll asa = min(solve1(), solve2());
        cout << asa << "\n";
        return 0;
    }

    return 0;
}

/*

in:
1 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
ans: 24

in:
2 5
B 0 A 4
B 1 B 3
A 5 B 7
B 2 A 6
B 1 A 7
ans: 22

in:
2 3
A 0 B 5
A 0 B 4
A 1 B 5

*/

Compilation message (stderr)

bridge.cpp: In function 'll solve2()':
bridge.cpp:129:8: warning: unused variable 'cur' [-Wunused-variable]
  129 |     ll cur = 0;
      |        ^~~

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 9 / 9
• Subtask 4: 32 / 32
• Subtask 5: 37 / 37