Submission #1113945

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113945		mariaclara	Alternating Current (BOI18_alternating)	C++17	19 / 100	56 ms	3144 KiB

alternating

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
const int MAXN = 1e5+5;
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mk make_pair 
#define pb push_back
#define fr first 
#define sc second 

int n, m, group[MAXN];
int main() {

    cin >> n >> m;
    vector<pair<pii,int>> v(m);

    for(int i = 0; i < m; i++) {
        cin >> v[i].fr.fr >> v[i].fr.sc;
        if(v[i].fr.fr > v[i].fr.sc) v[i].fr.sc += n;
        v[i].sc = i;
    }

    sort(all(v));
    auto [A,B] = v[0].fr;
    bool possible = 0;

    for(int i = 1; i <= 1; i++) {
        // i é o primeiro elemento do 2° grupo
        group[v[i].sc] = 1;
        auto [C,D] = v[i].fr;

        int B_ = B;
        for(int j = i+1; j < sz(v); j++) {
            if(B_ <= D and B_ - A < n - 1) {
                if(v[j].fr.fr <= B_+1) B_ = max(B_, v[j].fr.sc);
                group[v[j].sc] = 0;
            }
            else {
                if(v[j].fr.fr <= D+1) D = max(D, v[j].fr.sc);
                group[v[j].sc] = 1;
            }
        }
        
        if(B_ - A >= n-1 and D - C >= n-1) {
            possible = 1;
            break;
        }

        group[v[i].sc] = 0;
        if(v[i].fr.fr <= B+1) B = max(B, v[i].fr.sc);
    }

    if(!possible) {
        cout << "impossible\n";
        return 0;
    }

    for(int i = 0; i < m; i++) cout << group[i];
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 20
• Subtask 3: 0 / 22
• Subtask 4: 19 / 19
• Subtask 5: 0 / 26