Submission #589920

#	Time	Username	Problem	Language	Result	Execution time	Memory
589920		dxz05	Palembang Bridges (APIO15_bridge)	C++14	63 / 100	2083 ms	12412 KiB

bridge

#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << "[" << H << "]";
    debug_out(T...);
}

#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair

clock_t startTime;

double getCurrentTime() {
    return (double) (clock() - startTime) / CLOCKS_PER_SEC;
}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e6 + 3e2;
const int M = 5555;

long long Solve_One_Bridge(const vector<int> &a, const vector<int> &b){
    vector<int> c;
    for (int i : a) c.push_back(i);
    for (int i : b) c.push_back(i);

    sort(all(c));

    long long res = 0;
    int mid = c[(int)c.size() / 2 - 1];

    for (int i : c) res += abs(i - mid);

    return res;
}

long long cost(const vector<int> &a, const vector<int> &b, int x, int y){
    ll res = 0;
    for (int i = 0; i < a.size(); i++){
        res += min(abs(a[i] - x) + abs(b[i] - x), abs(a[i] - y) + abs(b[i] - y));
    }
    return res;
}

void solve(int TC) {
    int k, n;
    cin >> k >> n;

    long long ans = 0;

    vector<int> a, b;
    while (n--){
        char p, q;
        int x, y;
        cin >> p >> x >> q >> y;

        if (p == q){
            ans += abs(x - y);
        } else {
            ans++;
            if (x > y) swap(x, y);
            a.push_back(x);
            b.push_back(y);
        }

    }

    n = a.size();

    if (n == 0){
        cout << ans << endl;
        return;
    }

    if (k == 1) {
        cout << ans + Solve_One_Bridge(a, b) << endl;
        return;
    }

    set<int> positions;
    for (int i : a) positions.insert(i);
    for (int i : b) positions.insert(i);

    vector<int> pos;
    for (int i : positions) pos.push_back(i);

    ll best = LLINF;
    for (int i = 0; i < pos.size(); i++){
        int x = pos[i];
        int l = i, r = pos.size() - 1;
        while (r - l >= 3){
            int m1 = l + (r - l) / 3;
            int m2 = r - (r - l) / 3;

            ll f1 = cost(a, b, x, pos[m1]);
            ll f2 = cost(a, b, x, pos[m2]);

            best = min({best, f1, f2});

            if (f1 > f2){
                l = m1;
            } else {
                r = m2;
            }
        }

        for (int j = l; j <= r; j++) best = min(best, cost(a, b, x, pos[j]));
    }

    cout << ans + best << endl;

}

int main() {
    startTime = clock();
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

#ifdef dddxxz
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int TC = 1;
    //    cin >> TC;

    for (int test = 1; test <= TC; test++) {
        //debug(test);
        //cout << "Case #" << test << ": ";
        solve(test);
    }

#ifdef dddxxz
    cerr << endl << "Time: " << int(getCurrentTime() * 1000) << " ms" << endl;
#endif

    return 0;
}

Compilation message (stderr)

bridge.cpp: In function 'long long int cost(const std::vector<int>&, const std::vector<int>&, int, int)':
bridge.cpp:61:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for (int i = 0; i < a.size(); i++){
      |                     ~~^~~~~~~~~~
bridge.cpp: In function 'void solve(int)':
bridge.cpp:110:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  110 |     for (int i = 0; i < pos.size(); i++){
      |                     ~~^~~~~~~~~~~~

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