Submission #1258643

#	Time	Username	Problem	Language	Result	Execution time	Memory
1258643		gojo1107	Palembang Bridges (APIO15_bridge)	C++20	0 / 100	1 ms	328 KiB

bridge

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fast_io ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fr(i,a,b) for (int i=a; i<b; i++)
#define loop(x,n) for (int x=0; x<n; x++)
#define mod 1000000007
#define inf (1LL<<60)
#define all(x) (x).begin(), (x).end()
typedef long double lld;
typedef unsigned long long ull;

#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif

void _print(long long t) {cerr << t;}
void _print(int t) {cerr << t;}
void _print(string t) {cerr << t;}
void _print(char t) {cerr << t;}
void _print(lld t) {cerr << t;}
void _print(double t) {cerr << t;}
void _print(ull t) {cerr << t;}
template <class T, class V> void _print(pair <T, V> p);
template <class T> void _print(vector <T> v);
template <class T> void _print(set <T> v);
template <class T, class V> void _print(map <T, V> v);
template <class T> void _print(multiset <T> v);
template <class T, class V> void _print(pair <T, V> p) {cerr << "{"; _print(p.first); cerr << ","; _print(p.second); cerr << "}";}
template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T> void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

bool cmp (pair<int,int> a, pair<int,int> b) {
    return a.first + a.second < b.first + b.second;
}

class SlidingMedian {
    priority_queue<int> left_max; // <= median
    priority_queue<int, vector<int>, greater<int>> right_min; // >= median
    long long sum_left = 0, sum_right = 0;

    void balance() {
        if (left_max.size() > right_min.size() + 1) {
            int val = left_max.top(); left_max.pop();
            sum_left -= val;
            right_min.push(val);
            sum_right += val;
        } else if (right_min.size() > left_max.size()) {
            int val = right_min.top(); right_min.pop();
            sum_right -= val;
            left_max.push(val);
            sum_left += val;
        }
    }

public:
    void add(int num) {
        if (left_max.empty() || num <= left_max.top()) {
            left_max.push(num);
            sum_left += num;
        } else {
            right_min.push(num);
            sum_right += num;
        }
        balance();
    }

    // Use LOWER median always (assumes left.size() >= right.size())
    int median() const {
        return left_max.top();
    }

    long long cost() const {
        long long m = median();
        // sum |a - m| = m*L - sum_left + sum_right - m*R
        return m * 1LL * left_max.size() - sum_left
               + sum_right - m * 1LL * right_min.size();
    }
};

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

    long long ans = 0;
    vector<pair<int,int>> a;
    a.reserve(n);

    for (int i = 0; i < n; i++) {
        char ch1, ch2;
        int p, s;
        cin >> ch1 >> p >> ch2 >> s;
        if (ch1 == ch2) {
            ans += llabs(1LL * s - p);
        } else {
            a.pb({p, s});
        }
    }

    if (a.empty()) { // nothing to pair/split
        cout << ans << '\n';
        return;
    }

    sort(all(a), cmp);

    SlidingMedian s1, s2;
    int m = (int)a.size();
    vector<long long> pre(m), suf(m);

    for (int i = 0; i < m; i++) {
        s1.add(a[i].first);
        s1.add(a[i].second);
        pre[i] = s1.cost();
    }
    debug(pre);

    for (int i = m - 1; i >= 0; i--) {
        s2.add(a[i].first);
        s2.add(a[i].second);
        suf[i] = s2.cost();
    }
    debug(suf);

    long long res = LLONG_MAX;
    for (int i = 0; i < m ; i++) {
        res = min(res, pre[i] + suf[i ]);
    }


    cout << (res + ans) << '\n';
}

int main() {
#ifndef ONLINE_JUDGE
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
    freopen("Error.txt", "w", stderr);
#endif
    fast_io;
    cout.setf(std::ios::fixed); cout<<setprecision(10);
    int t = 1;
    // cin >> t;
    while (t--) solve();
}

Compilation message (stderr)

bridge.cpp: In function 'int main()':
bridge.cpp:141:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  141 |     freopen("input.txt","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
bridge.cpp:142:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  142 |     freopen("output.txt","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
bridge.cpp:143:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  143 |     freopen("Error.txt", "w", stderr);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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