Submission #229112

#	Time	Username	Problem	Language	Result	Execution time	Memory
229112		parsa_mobed	Palembang Bridges (APIO15_bridge)	C++14	22 / 100	103 ms	15440 KiB

bridge

#include <bits/stdc++.h>

using namespace std;
#define int long long
#define all(v) v.begin(), v.end()
#define sz(v) (int)v.size()
#define pii pair <int , int>
#define F first
#define S second
#define L first
#define R second
const int N = 2e5 + 5, M = 2e3 + 5, inf = 1e18;
int prf[N], suf[N], prf_cost[N], suf_cost[N], ss[N], ps[N], cost[M][M], cnt[M][M];
vector <int> P;
vector <pii> seg;

int32_t main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int n, k, ans = 0; cin >> k >> n;
    for (int i = 0; i < n; i++) {
        char s, e; int x1, x2; cin >> s >> x1 >> e >> x2;
        if (x1 > x2) swap(x1, x2);
        ans += x2 - x1;
        if (s != e) ans++, P.push_back(x1), P.push_back(x2), seg.push_back({x1, x2});
    }
    sort(all(P)), P.resize(unique(all(P)) - P.begin());
    int m = sz(P);
    for (pii p : seg) {
        int l = lower_bound(all(P), p.L) - P.begin(), r = lower_bound(all(P), p.R) - P.begin();
        suf[l]++, prf[r]++, ss[l] += p.L, ps[r] += p.R;
    }
    for (int i = m - 1; i >= 0; i--) suf[i] += suf[i + 1], ss[i] += ss[i + 1];
    for (int i = 1; i < m; i++) prf[i] += prf[i - 1], ps[i] += ps[i - 1];
    int res = inf;
    for (int i = 0; i < m; i++)
        prf_cost[i] =  P[i] * prf[i] - ps[i], suf_cost[i] = ss[i] - P[i] * suf[i], res = min(res, prf_cost[i] + suf_cost[i]);
    if (k == 2) {
        for (pii p : seg) {
            int l = lower_bound(all(P), p.L) - P.begin(), r = lower_bound(all(P), p.R) - P.begin();
            cnt[l][r]++;
        }
        for (int len = 2; len <= m; len++) {
            for (int l = 0, r = len - 1; r < m; l++, r++) {
                if (len > 2) cost[l][r] = cost[l + 1][r - 1] + cnt[l + 1][r - 1];
                cnt[l][r] += cnt[l][r - 1] + cnt[l + 1][r] - (l + 1 <= r - 1 ? cnt[l + 1][r - 1] : 0);
            }
        }
        for (int i = 0; i < m; i++) for (int j = i + 1; j < m; j++) {
            //res = min(res, prf_cost[i] + suf_cost[j] + cost[i][j]);
            int x = P[i], y = P[j], sum = prf_cost[i] + suf_cost[j], c = 0;
            for (pii p : seg) if (x <= p.L && p.R <= y) sum += min(p.L - x, y - p.R), c++;
            if (sum != cost[i][j]) assert(cost[i][j] > sum);
            res = min(res, sum);
        }
    }
    if (res == inf) res = 0;
    cout << ans + res*2 << "\n";
}

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 0 / 9
• Subtask 4: 0 / 32
• Subtask 5: 0 / 37