oj.uz

답안 #882294

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
882294 2023-12-03T03:18:27 Z kh0i Joker (BOI20_joker) C++17
25 / 100
 1901 ms 35588 KB 
#include "bits/stdc++.h"
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif

using ll = long long;
using pii = pair<int, int>;

#define F first
#define S second
#define sz(x) (int)((x).size())
#define all(x) (x).begin(), (x).end()

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
    assert(l <= r);
    return uniform_int_distribution<ll> (l, r)(rng);
}

const int N = 2e5 + 3;

int n, m, q, L[N], R[N];
vector<pii> g[N];
pii e[N];

// contain no odd cycle -> bipartite graph

namespace Sub12{
    bool valid_input(){
        return n <= 2000 and m <= 2000 and q <= 2000;
    }

    int vis[N];

    bool dfs(int u, int l, int r, int col){
        bool ok = 1;
        vis[u] = col;
        for(auto [v, id] : g[u]){
            if(l <= id and id <= r)
                continue;
            if(vis[v])
                ok &= (vis[u] != vis[v]);
            else
                ok &= dfs(v, l, r, col ^ 3);
        }
        return ok;
    }

    void solve(){
        for(int i = 1; i <= q; ++i){
            bool bipartite = 1;
            for(int u = 1; u <= n; ++u)
                vis[u] = 0;
            for(int u = 1; u <= n; ++u){
                if(!vis[u])
                    bipartite &= dfs(u, L[i], R[i], 1);
            }
            cout << (bipartite ? "NO\n" : "YES\n");
        }
    }
}

struct DSU{
    bool bipartite = 1;
    vector<pii> p;
    int n;

    void init(int _n){
        n = _n;
        p.resize(n + 2);
        for(int i = 1; i <= n; ++i)
            p[i] = {i, 0};
    }

    pii find_set(int u){
        if(u != p[u].F){
            int parity = p[u].S;
            p[u] = find_set(p[u].F);
            p[u].S ^= parity;
        }
        return p[u];
    }

    void add_edge(int u, int v){
        pii pu = find_set(u);
        u = pu.F;
        pii pv = find_set(v);
        v = pv.F;
        int x = pu.S, y = pv.S;
        if(u == v){
            bipartite &= (x != y);
            return;
        }
        p[v] = {u, x ^ y ^ 1};
    }
};

namespace Sub34{
    bool valid_input(){
        bool ok = 1;
        for(int i = 1; i <= q; ++i)
            ok &= (L[i] <= 200);
        return ok;
    }

    int ans[N];
    vector<pii> d[N];

    void solve(){
        for(int i = 1; i <= q; ++i){
            d[L[i]].push_back({R[i], i});
        }
        for(int i = 1; i <= min(200, m); ++i){
            DSU dsu;
            dsu.init(n);
            for(int j = 1; j < i; ++j){
                dsu.add_edge(e[j].F, e[j].S);
            }
            sort(all(d[i]), [](pii &x, pii &y) -> bool{
                 return x.F < y.F;
            });

            for(int j = m; j >= i; --j){
                while(!d[i].empty() and d[i].back().F == j){
                    ans[d[i].back().S] = dsu.bipartite;
                    d[i].pop_back();
                }
                dsu.add_edge(e[j].F, e[j].S);
            }
        }
        for(int i = 1; i <= q; ++i)
            cout << (ans[i] ? "NO\n" : "YES\n");
    }
}

struct DSU_Rollback{
    vector<int> p, c;
    vector<array<int, 5>> op;
    bool bipartite = 1;

    void init(int n){
        p.clear();
        p.resize(n + 2, -1);
        c.clear();
        c.resize(n + 2, 0);
    }

    pii get(int x){
        int d = 0;
        while(p[x] >= 0){
            d ^= c[x];
            x = p[x];
        }
        return {x, d};
    }

    void join_sets(int u, int v){
        debug("JOIN", u, v);
        pii pu = get(u), pv = get(v);
        op.push_back({pu.F, pv.F, p[pu.F], p[pv.F], bipartite});
        if(pu.F == pv.F){
            bipartite &= (pu.S != pv.S);
            return;
        }
        if(p[pu.F] > p[pv.F])
            swap(pu, pv);
        p[pu.F] += p[pv.F];
        p[pv.F] = pu.F;
        c[pv.F] = pu.S ^ pv.S ^ 1;
        return;
    }

    void rollback(){
        debug("ROLL");
        array<int, 5> x = op.back();
        op.pop_back();
        if(x[0] == -1) return;
        p[x[0]] = x[2], p[x[1]] = x[3];
        bipartite = x[4];
    }
};

namespace Sub5{
    bool valid_input(){
        return q <= 2000;
    }

    int B, add_time[N];
    vector<int> blk[N];
    int ans[N];

    void solve(){
        B = m / sqrt(q);
        debug(B);
        for(int i = 1; i <= q; ++i)
            blk[(L[i] + B - 1) / B].push_back(i);

        for(int bl = 1; bl < N; ++bl){
            if(blk[bl].empty())
                continue;
            vector<int> &d = blk[bl];
            debug(d);
            sort(all(d), [](int &x, int &y) -> bool {
                 return R[x] < R[y];
            });
            DSU_Rollback dsu;
            dsu.init(n);

            int timer = 0;
            int U = (bl - 1) * B + 1;

            debug(U);

            for(int i = 1; i < U; ++i)
                dsu.join_sets(e[i].F, e[i].S);

            for(int i = m; i > R[d.front()]; --i)
                dsu.join_sets(e[i].F, e[i].S);

            int cur = R[d.front()] + 1;

            for(int x : d){
                debug(L[x], R[x], cur);
                while(cur <= R[x]){
                    dsu.rollback();
                    ++cur;
                }

                int last = timer;
                debug(last);

                for(int i = U + 1; i <= L[x]; ++i)
                    dsu.join_sets(e[i].F, e[i].S);
                ans[x] = dsu.bipartite;
                for(int i = U + 1; i <= L[x]; ++i)
                    dsu.rollback();
            }
        }
        for(int i = 1; i <= q; ++i)
            cout << (ans[i] ? "NO\n" : "YES\n");
    }
};

void solve(){
    cin >> n >> m >> q;
    for(int i = 1; i <= m; ++i){
        int u, v;
        cin >> u >> v;
        g[u].push_back({v, i});
        g[v].push_back({u, i});
        e[i] = {u, v};
    }
    for(int i = 1; i <= q; ++i)
        cin >> L[i] >> R[i];
    if(Sub5::valid_input())
        Sub5::solve();
    else if(Sub12::valid_input())
        Sub12::solve();
    else if(Sub34::valid_input())
        Sub34::solve();

}

int32_t main() {
    cin.tie(nullptr)->sync_with_stdio(0);
    #define task "nohome"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int test = 1;
//    cin >> test;
    for(int i = 1; i <= test; ++i){
//        cout << "Case #" << i << ": ";
        solve();
    }
    #ifdef LOCAL
        cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    #endif
    return 0;
}

Compilation message

Joker.cpp: In function 'void Sub5::solve()':
Joker.cpp:233:21: warning: unused variable 'last' [-Wunused-variable]
  233 |                 int last = timer;
      |                     ^~~~
Joker.cpp: In function 'int32_t main()':
Joker.cpp:272:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  272 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:273:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  273 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 19036 KB Output is correct
2 Correct 4 ms 19036 KB Output is correct
3 Correct 4 ms 19032 KB Output is correct
4 Correct 4 ms 19088 KB Output is correct
5 Correct 4 ms 19032 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19032 KB Output is correct
8 Incorrect 4 ms 19036 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #2
0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 19036 KB Output is correct
2 Correct 4 ms 19036 KB Output is correct
3 Correct 4 ms 19032 KB Output is correct
4 Correct 4 ms 19088 KB Output is correct
5 Correct 4 ms 19032 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19032 KB Output is correct
8 Incorrect 4 ms 19036 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #3
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 19036 KB Output is correct
2 Correct 4 ms 19036 KB Output is correct
3 Correct 666 ms 32756 KB Output is correct
4 Correct 634 ms 35292 KB Output is correct
5 Correct 1331 ms 35588 KB Output is correct
6 Correct 808 ms 33988 KB Output is correct
7 Correct 798 ms 33816 KB Output is correct
8 Correct 1359 ms 32656 KB Output is correct
9 Correct 1750 ms 33412 KB Output is correct
10 Correct 1874 ms 35128 KB Output is correct
11 Correct 1312 ms 33664 KB Output is correct
12 Correct 1476 ms 35264 KB Output is correct
13 Correct 653 ms 32200 KB Output is correct
14 Correct 1345 ms 33216 KB Output is correct
15 Correct 1901 ms 34572 KB Output is correct
16 Correct 1868 ms 35424 KB Output is correct

Subtask #4
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 19036 KB Output is correct
2 Correct 4 ms 19036 KB Output is correct
3 Correct 4 ms 19032 KB Output is correct
4 Correct 4 ms 19088 KB Output is correct
5 Correct 4 ms 19032 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19032 KB Output is correct
8 Incorrect 4 ms 19036 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #5
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 19036 KB Output is correct
2 Correct 4 ms 19036 KB Output is correct
3 Correct 4 ms 19032 KB Output is correct
4 Correct 4 ms 19088 KB Output is correct
5 Correct 4 ms 19032 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19032 KB Output is correct
8 Incorrect 4 ms 19036 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #6
0 / 29.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 19036 KB Output is correct
2 Correct 4 ms 19036 KB Output is correct
3 Correct 4 ms 19032 KB Output is correct
4 Correct 4 ms 19088 KB Output is correct
5 Correct 4 ms 19032 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19032 KB Output is correct
8 Incorrect 4 ms 19036 KB Output isn't correct
9 Halted 0 ms 0 KB -