Submission #1057619

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057619		Celebi_276	Palembang Bridges (APIO15_bridge)	C++17	100 / 100	53 ms	7944 KiB

bridge

#include <bits/stdc++.h>
using namespace std;

#define PrintDec(d, c)    cout << fixed << setprecision(c) << d
#define   MultiTest(q)    long long q; cin >> q; while (q--)
#define        rall(v)    v.rbegin(), v.rend()
#define         all(v)    v.begin(), v.end()
#define           endl    "\n"
#define           NAME    "BRIDGES"
#define            ull    unsigned long long int
#define             ll    long long int
#define            pii    pair <int, int>
#define            pll    pair <ll, ll>

bool minimize (ll &a, ll b) {
    if (a > b) {
        return a = b, true;
    }
    return false;
}

bool maximize (ll &a, ll b) {
    if (a < b) {
        return a = b, true;
    }
    return false;
}

struct Pedestrian {
    int s, t;
    bool operator< (const Pedestrian &X) const {
        return s + t < X.s + X.t;
    }
};

const int N = 2E5 + 25;
priority_queue <int, vector<int>> L;
priority_queue <int, vector<int>, greater<int>> R;
int n, m, s, t, k;
vector <int> V;
vector <Pedestrian> A;
char c1, c2;
ll D, T, v1, v2, F[N], G[N];

signed main () {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    if (fopen(NAME".INP", "r")) {
        freopen(NAME".INP", "r", stdin);
        freopen(NAME".OUT", "w", stdout);
    }
    cin >> k >> n;
    V.push_back(0);
    A.push_back({0, 0});
    for (int i = 1; i <= n; i++) {
        cin >> c1 >> s >> c2 >> t;
        if (c1 == c2) D += llabs(s - t);
        else {
            if (s > t) swap(s, t);
            A.push_back({s, t});
            ++m;
            V.push_back(s);
            V.push_back(t);
        }
    }
    D += m;
    if (k == 1) {
        v1 = v2 = 0;
        sort(V.begin(), V.end());
        for (int i = 1; i <= 2 * m; i++) {
            v1 += abs(V[m] - V[i]);
            v2 += abs(V[m + 1] - V[i]);
        }
        cout << D + min(v1, v2);
    }
    else {
        sort(A.begin(), A.end());
        v1 = v2 = 0;
        for (int i = 1; i <= m; i++) {
            L.push(A[i].s); R.push(A[i].t);
            v1 += A[i].s; v2 += A[i].t;
            if (L.top() > R.top()) {
                int u = L.top(), v = R.top();
                v1 += v - u;
                v2 += u - v;
                L.pop(); R.pop();
                L.push(v); R.push(u);
            }
            F[i] = v2 - v1;
        }
        while (L.size()) L.pop();
        while (R.size()) R.pop();
        v1 = v2 = 0;
        for (int i = m; i >= 1; i--) {
            L.push(A[i].s); R.push(A[i].t);
            v1 += A[i].s; v2 += A[i].t;
            if (L.top() > R.top()) {
                int u = L.top(), v = R.top();
                v1 += v - u;
                v2 += u - v;
                L.pop(); R.pop();
                L.push(v); R.push(u);
            }
            G[i] = v2 - v1;
        }
        T = F[1] + G[2];
        for (int i = 2; i < m; i++)
            minimize(T, F[i] + G[i + 1]);
        cout << D + T;
    }
    return 0;
}

Compilation message (stderr)

bridge.cpp: In function 'int main()':
bridge.cpp:49:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         freopen(NAME".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bridge.cpp:50:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         freopen(NAME".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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