Submission #971348

#	Time	Username	Problem	Language	Result	Execution time	Memory
971348		socpite	Palembang Bridges (APIO15_bridge)	C++14	100 / 100	493 ms	29940 KiB

bridge

#include<bits/stdc++.h>
using namespace std;
 
long long INF = 1e18;
const int maxn = 1e5+5;
 
vector<int> cp;
 
vector<pair<int, int>> vec;
 
bool cmp(pair<int, int> a, pair<int, int> b){
    return a.first + a.second < b.first + b.second;
}

map<int, long long> mp[2];
long long pfx[maxn], sfx[maxn];

long long crr = -1, a, b;

void init(){
    mp[0].clear();
    mp[1].clear();
    mp[0][-1] = 0;
    crr = -1;
    a = 0;
    b = 0;
}

void upd_crr() {
    while(a < 0){
        crr = mp[0].upper_bound(crr)->first;
        a += mp[0][crr];
        b += mp[1][crr];
    }
    while(a > 0){
        a -= mp[0][crr];
        b -= mp[1][crr];
        crr = prev(mp[0].lower_bound(crr))->first;
    }
}

long long get_ans(){
    long long re = crr*a + b;
    auto it = mp[0].upper_bound(crr);
    if(it != mp[0].end())re = min(re, it->first*(a+it->second) + mp[1][it->first] + b);
    return re;
}

void add_new(int l, int r){
    if(crr < l){
        a--;
        b += l;
    }
    if(crr >= r){
        a++;
        b -= r;
    }
    mp[0][l]++;
    mp[0][r]++;
    mp[1][l]-=l;
    mp[1][r]-=r;
    upd_crr();
}

int k, n;
 
int main(){
    ios::sync_with_stdio(false);
    cin >> k >> n;
    long long ans = INF;
    long long base = 0;
    for(int i = 0; i < n; i++){
        char t1, t2;
        pair<int, int> p;
        cin >> t1 >> p.first >> t2 >> p.second;
        if(p.first > p.second)swap(p.first, p.second);
        base += p.second - p.first;
        if(t1 != t2) {
            base++;
            vec.push_back(p);
            cp.push_back(p.first);
            cp.push_back(p.second);
        }
    }
    if(vec.empty()){
        cout << base;
        return 0;
    }
    sort(vec.begin(), vec.end(), cmp);
    init();
    for(int i = 0; i < vec.size(); i++){
        add_new(vec[i].first, vec[i].second);
        pfx[i] = get_ans();
    }
    if(k == 1){
        cout << base + pfx[vec.size()-1]*2;
        return 0;
    }
    init();
    for(int i = vec.size()-1; i >= 0; i--){
        add_new(vec[i].first, vec[i].second);
        sfx[i] = get_ans();
        if(i)ans = min(ans, pfx[i-1] + sfx[i]);
        else ans = min(ans, sfx[i]);
    }
    cout << base + ans*2;
    
}

Compilation message (stderr)

bridge.cpp: In function 'int main()':
bridge.cpp:91:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |     for(int i = 0; i < vec.size(); i++){
      |                    ~~^~~~~~~~~~~~

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