Submission #978417

#	Time	Username	Problem	Language	Result	Execution time	Memory
978417		nnin	Palembang Bridges (APIO15_bridge)	C++17	22 / 100	34 ms	4904 KiB

bridge

#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
using ll = long long;
#define f first
#define s second
 
vector<pii> cross;
int N, K;
 
ll check1(int bridge) {
    ll ret = 0;
    for(auto [st, en]:cross) {
        if(bridge<st) ret += (ll)st-bridge+en-bridge;
        else if(bridge>en) ret += (ll)bridge-st+bridge-en;
        else ret += (ll)en-st;
    }
    return ret;
}
 
ll check2(int br1, int br2) {
    ll ret = 0;
    for(auto [st, en]:cross) {
        if((st<=br1&&br1<=en) || (st<=br2&&br2<=en)) ret += (ll)en-st;
        else if(br2<st) ret += (ll)st-br2+en-br2;
        else if(br1>en) ret += (ll)br1-st+br1-en;
        else ret += min((ll)st-br1+en-br1, (ll)br2-st+br2-en);
    }
    return ret;
}
 
ll one() {
    vector<int> v;
    for(auto [st, en]:cross) {
        v.push_back(st);
        v.push_back(en);
    }
    sort(v.begin(), v.end());
    return min(check1(v[((int)v.size()-1)/2]), check1(v[(int)v.size()/2]));
}
 
ll two() {
    vector<int> v;
    for(auto [st, en]:cross) {
        v.push_back(st);
        v.push_back(en);
    }
    sort(v.begin(), v.end());
    int med1 = ((int)v.size()-1)/2;
    int med2 = (int)v.size()/2;
    set<int> l, r;
    l.insert(v[med1/2]);
    l.insert(v[(med1+1)/2]);
    l.insert(v[med2/2]);
    l.insert(v[(med2+1)/2]);
    r.insert(v[(med1+v.size()-1)/2]);
    r.insert(v[(med1+v.size())/2]);
    r.insert(v[(med2+v.size()-1)/2]);
    r.insert(v[(med2+v.size())/2]);
    ll ret = 1e18;
    for(int med1:l) for(int med2:r) {
        ret = min(ret, check2(med1, med2));
    }
    return ret;
}
 
int main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    cin>>K>>N;
    ll ans = 0;
    for(int i=0;i<N;i++) {
        char z1, z2;
        int b1, b2;
        cin>>z1>>b1>>z2>>b2;
        if(z1==z2) {
            ans += abs(b1-b2);
        } else {
            cross.push_back({min(b1, b2), max(b1, b2)});
        }
    }
    if(cross.empty()) {
        cout<<ans;
        return 0;
    }
    ans += cross.size();
    if(K==1) cout<<ans+one();
    else cout<<ans+two();
}

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