oj.uz

Submission #768233

# Submission time Handle Problem Language Result Execution time Memory
768233 2023-06-27T19:02:04 Z oyber Joker (BOI20_joker) C++14
25 / 100
 86 ms 10080 KB 
#include <cstdio>
#include <vector>
#include <algorithm>
#include <functional>
#include <stack>
using namespace std;

vector<int> u;
vector<int> s;
vector<int> p;

int find(int n) {
    if (u[n] == n) return n;
    return find(u[n]);
}

int find_compress(int n) {
    if (u[n] == n) return n;
    int r = find_compress(u[n]); 
    if (p[u[n]] != p[r]) p[n] = !p[n];
    u[n] = r;
    return u[n];
}

int parity(int n) {
    if (u[n] == n) return 0;
    return parity(u[n])^p[n];
}

struct UniteInfo {
    int a;
    int b;
    int sa;
};

UniteInfo unite(int a, int b) {
    int ap = find(a);
    int bp = find(b);
    if (s[bp] > s[ap]) {
        swap(a, b);
        swap(ap, bp);
    }
    u[bp] = ap;
    s[ap] += s[bp];
    if (parity(a) == parity(b)) {
        p[bp] = 1;
    } else {
        p[bp] = 0;
    }
    return UniteInfo {
        ap,
        bp,
        s[ap] - s[bp],
    };
}

void undo(UniteInfo info) {
    u[info.b] = info.b;
    s[info.a] = info.sa;
    p[info.b] = 0;
}

struct Query {
    int l;
    int r;
    int i;
};

bool comp_query(Query q1, Query q2) {
    return q1.r > q2.r;
}

bool comp_query2(Query q1, Query q2) {
    return q1.l < q2.l;
}

int main() {
    int n, m, qn;
    scanf("%d %d %d", &n, &m, &qn);

    u.resize(n);
    s.resize(n, 1);
    p.resize(n);


    vector<pair<int, int>> e(m);
    for (int i = 0; i < m; i++) {
        int a, b; 
        scanf("%d %d", &a, &b);
        a--;b--;
        e[i] = make_pair(a, b);
        //printf("%d %d %d\n", a, b, i);
    }

    vector<Query> q(qn);
    for (int i = 0; i < qn; i++) {
        int l, r;
        scanf("%d %d", &l, &r);
        l--;r--;
        q[i] = Query{l,r,i};
    }
    sort(q.begin(), q.end(), comp_query2);

    int group_size = 1024;
    int group_num = q[q.size()-1].l / group_size + 1;
    //printf("%d %d\n", int(q[q.size()-1].l), group_num);
    vector<vector<Query>> groups(group_num);
    int j = 0;
    for (int i = 0; i < group_num; i++) {
        while (j < qn) {
            if (q[j].l >= (i+1)*group_size) break;
            groups[i].push_back(q[j]);
            //printf("g: %d q: %d\n", i, q[j].i);
            j++;
        }
        sort(groups[i].begin(), groups[i].end(), comp_query);
    }

    vector<UniteInfo> infos;
    vector<bool> result(qn);
    for (int j = 0; j < group_num; j++) {
        if (groups[j].size() == 0) break;

        //reset state
        for (int i = 0; i < n; i++) {
            u[i] = i;
            s[i] = 1;
            p[i] = 0;
        }

        bool l_cycle = false;
        int current_l = 0;
        for (; current_l < groups[j][0].l; current_l++) {
            int a = e[current_l].first;
            int b = e[current_l].second;
            //printf("%d %d %d\n", current_l, a, b);
            if (find(a) == find(b)) {
                if (parity(a) == parity(b)) {
                    l_cycle = true;
                    break;
                }
            } else {
                unite(a, b);
            }
        }
        //printf("l: %d\n", current_l);


        int current_r = m-1;
        bool r_cycle = false;
        for (int i = 0; i < int(groups[j].size()); i++) {
            if (r_cycle || l_cycle) {
                result[groups[j][i].i] = true;
                continue;
            }
            int l = groups[j][i].l;
            int r = groups[j][i].r;
            //printf("%d: %d %d\n", i, l, r);

            while (current_r > r) {
                int a = e[current_r].first;
                int b = e[current_r].second;
                //printf("%d %d %d\n", current_r, a, b);
                if (find(a) == find(b)) {
                    if (parity(a) == parity(b)) {
                        r_cycle = true;
                        break;
                    }
                } else {
                    unite(a, b);
                }
                current_r--;
            }

            if (r_cycle) {
                result[groups[j][i].i] = true;
                continue;
            }

            bool cycle = false;
            for (int c_l = current_l; c_l < l; c_l++) {
                int a = e[c_l].first;
                int b = e[c_l].second;
                //printf("%d %d %d\n", current_l, a, b);
                if (find(a) == find(b)) {
                    if (parity(a) == parity(b)) {
                        cycle = true;
                        break;
                    }
                } else {
                    infos.push_back(unite(a, b));
                }
            }
            if (cycle) {
                result[groups[j][i].i] = true;
            }
            while (infos.size() > 0) {
                undo(infos.front());
                infos.pop_back();
            }
        }
    }

    for (int i = 0; i < qn; i++) {
        if (result[i]) {
            printf("YES\n");
        } else {
            printf("NO\n");
        }
    }
}

Compilation message

Joker.cpp: In function 'int main()':
Joker.cpp:79:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |     scanf("%d %d %d", &n, &m, &qn);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:89:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         scanf("%d %d", &a, &b);
      |         ~~~~~^~~~~~~~~~~~~~~~~
Joker.cpp:98:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         scanf("%d %d", &l, &r);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 288 KB Output is correct
3 Correct 0 ms 288 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Incorrect 0 ms 212 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 288 KB Output is correct
3 Correct 0 ms 288 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Incorrect 0 ms 212 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 288 KB Output is correct
3 Correct 83 ms 8812 KB Output is correct
4 Correct 82 ms 9988 KB Output is correct
5 Correct 79 ms 9724 KB Output is correct
6 Correct 76 ms 8820 KB Output is correct
7 Correct 77 ms 8788 KB Output is correct
8 Correct 81 ms 8396 KB Output is correct
9 Correct 77 ms 8812 KB Output is correct
10 Correct 86 ms 10080 KB Output is correct
11 Correct 80 ms 8812 KB Output is correct
12 Correct 77 ms 9724 KB Output is correct
13 Correct 84 ms 7856 KB Output is correct
14 Correct 79 ms 8328 KB Output is correct
15 Correct 77 ms 9284 KB Output is correct
16 Correct 81 ms 9928 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 288 KB Output is correct
3 Correct 0 ms 288 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Incorrect 0 ms 212 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 288 KB Output is correct
3 Correct 0 ms 288 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Incorrect 0 ms 212 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 288 KB Output is correct
3 Correct 0 ms 288 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Incorrect 0 ms 212 KB Output isn't correct
6 Halted 0 ms 0 KB -