oj.uz

Submission #1042068

# Submission time Handle Problem Language Result Execution time Memory
1042068 2024-08-02T13:54:07 Z ProtonDecay314 Parachute rings (IOI12_rings) C++17
100 / 100
 1520 ms 126248 KB 
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pi;
typedef pair<ll, ll> pll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
typedef vector<vpi> vvpi;
typedef vector<vpll> vvpll;
typedef vector<bool> vb;
#define IOS ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
#define L(varll, mn, mx) for(ll varll = (mn); varll < (mx); varll++)
#define LR(varll, mx, mn) for(ll varll = (mx); varll > (mn); varll--)
#define LI(vari, mn, mx) for(int vari = (mn); vari < (mx); vari++)
#define LIR(vari, mx, mn) for(int vari = (mx); vari > (mn); vari--)
#define INPV(varvec) for(auto& varveci : (varvec)) cin >> varveci
#define fi first
#define se second
#define pb push_back
#define INF(type) numeric_limits<type>::max()
#define NINF(type) numeric_limits<type>::min()
#define TCASES int t; cin >> t; while(t--)

class UF {
    public:
        vi par;
        vi csize;
        int n;
        int ncomps;

        UF(int a_n): par(a_n, 0), csize(a_n, 1), n(a_n), ncomps(a_n) {
            for(int i = 0; i < n; i++) {
                par[i] = i;
            }
        }

        int find(int i) {
            while(i != par[i]) {
                par[i] = par[par[i]];
                i = par[i];
            }

            return i;
        }

        int conn(int i, int j) {
            return find(i) == find(j);
        }

        void unify(int i, int j) {
            int pari = find(i), parj = find(j);
            if(pari == parj) return;

            if(csize[pari] < csize[parj]) {
                par[pari] = parj;
                csize[parj] += csize[pari];
            } else {
                par[parj] = pari;
                csize[pari] += csize[parj];
            }

            ncomps--;
        }
};

int N;

vector<int> comps_with_cycle;
bool found_two_cycles = false;
int three_node = -1;

vvi adj;
UF *uf;
vector<UF> ufs;

int ans;
vi crit;
vvi degs;

bool is_crit(int cur_n) {
    vb conn(N, false);
    for(int j: adj[cur_n]) {
        conn[j] = true;
    }

    int num_1s = 0;
    int num_0s = 0;
    for(int i = 0; i < N; i++) {
        if(i == cur_n) continue;
        int sz = adj[i].size();
        if(conn[i]) {
            sz--;
        }
        if(sz >= 3) return false;
        if(sz == 1) num_1s++;
        if(sz == 0) num_0s++;
    }

    // ! DFS could be optimized
    stack<int> st;
    vb vis(N, false);

    int cid = 0;
    for(int s = 0; s < N; s++) {
        if(s == cur_n) {
            continue;
        }
        if(!vis[s]) {
            st.push(s);

            while(!st.empty()) {
                int i = st.top();
                st.pop();
                if(vis[i]) continue;
                vis[i] = true;

                for(int j : adj[i]) {
                    if(j == cur_n) continue;
                    st.push(j);
                }
            }
            cid++;
        }
    }

    return ((num_1s & 0b1) == 0 && (num_1s >> 1) + num_0s == cid);
}

// void upd_neighborhood() {
//     neighborhoud_crit.clear();
//     for(int i : crit) {
//         neighborhoud_crit.insert(i);

//         for(int j : adj[i]) {
//             neighborhoud_crit.insert(j);
//         }
//     }
// }

void Init(int N_) {
    N = N_;
    ans = N;
    uf = new UF(N);
    for(int i = 0; i < N; i++) {
        vi adjr;
        adj.pb(adjr);
    }
}

void create_ufs_and_degs() {
    ufs.clear();
    int ind = 0;
    for(int i : crit) {
        ufs.pb({N});
        vi degr(N, 0);
        degs.pb(degr);

        for(int i1 = 0; i1 < N; i1++) {
            if(i1 == i) continue;
            for(int i2 : adj[i1]) {
                if(i2 == i) continue;
                ufs.back().unify(i1, i2);
            }
        }

        for(int i1 = 0; i1 < N; i1++) {
            for(int j : adj[i1]) {
                if(j == i) continue;
                degs[ind][i1]++;
            }
        }
        ind++;
    }
}

void Link(int A, int B) {
    if(ans == 0) return; // refuse to even process haha
    
    int ncyclecomps = comps_with_cycle.size();
    if(ncyclecomps < 2) {
        if(ncyclecomps > 0) {
            comps_with_cycle[0] = uf->find(comps_with_cycle[0]);
        }
        if(uf->conn(A, B)) {
            // Possible cycle
            int poss_cycle_comp = uf->find(A);

            if(ncyclecomps == 0 || poss_cycle_comp != comps_with_cycle[0]) comps_with_cycle.pb(poss_cycle_comp);
        }
    }
    ncyclecomps = comps_with_cycle.size();
    if(comps_with_cycle.size() == 2) {
        ans = 0;
        return;
    }

    bool cycle_made = uf->conn(A, B);

    uf->unify(A, B);
    adj[A].pb(B);
    adj[B].pb(A);

    // Check comp sizes
    if(three_node == -1) {
        if(ncyclecomps == 1) {
            ans = uf->csize[uf->find(comps_with_cycle[0])];
        }
        if(adj[A].size() == 3) three_node = A;
        if(adj[B].size() == 3) three_node = B;

        // If you find a "three" node, immediately reprocess the graph
        // As in, check which ones of the neighbors of the three node are crit
        if(three_node != -1) {
            if(is_crit(three_node)) crit.pb(three_node);
            for(int i : adj[three_node]) {
                if(is_crit(i)) crit.pb(i);
            }

            ans = crit.size();

            create_ufs_and_degs();
        }
    } else {
        vi to_remove;

        for(int i = 0; i < ans; i++) {
            if(A == crit[i] || B == crit[i]) continue;
            degs[i][A]++;
            degs[i][B]++;
            bool made_three = degs[i][A] == 3 || degs[i][B] == 3;
            if(ufs[i].conn(A, B) || made_three) {
                to_remove.pb(i);
            }
            ufs[i].unify(A, B);
        }

        for(int i = to_remove.size() - 1; i >= 0; i--) {
            // cout << to_remove[i] << " ";
            crit.erase(next(crit.begin(), to_remove[i]));
            ufs.erase(next(ufs.begin(), to_remove[i]));
            degs.erase(next(degs.begin(), to_remove[i]));
        }
        // cout << endl;

        ans = crit.size();
    }

    // To simplify casework, idt we need the "four_node" thingy
    // if(four_node == -1) {
    //     if(adj[A].size() == 4) four_node = A;
    //     if(adj[B].size() == 4) four_node = B;
        
    //     // If you find a "four" node, immediately reprocess the graph
    // }
}

int CountCritical() {
    return ans;
}

Compilation message

rings.cpp: In function 'void Link(int, int)':
rings.cpp:201:10: warning: unused variable 'cycle_made' [-Wunused-variable]
  201 |     bool cycle_made = uf->conn(A, B);
      |          ^~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 3 ms 1056 KB Output is correct
3 Correct 2 ms 860 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 1 ms 600 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 796 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 3 ms 1052 KB Output is correct
10 Correct 3 ms 1052 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 161 ms 39848 KB Output is correct
2 Correct 725 ms 92408 KB Output is correct
3 Correct 175 ms 83884 KB Output is correct
4 Correct 503 ms 77112 KB Output is correct
5 Correct 480 ms 76396 KB Output is correct
6 Correct 522 ms 74612 KB Output is correct
7 Correct 187 ms 83580 KB Output is correct
8 Correct 1281 ms 118264 KB Output is correct
9 Correct 1520 ms 126248 KB Output is correct
10 Correct 346 ms 74416 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 3 ms 1056 KB Output is correct
3 Correct 2 ms 860 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 1 ms 600 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 796 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 3 ms 1052 KB Output is correct
10 Correct 3 ms 1052 KB Output is correct
11 Correct 3 ms 1052 KB Output is correct
12 Correct 4 ms 1368 KB Output is correct
13 Correct 6 ms 1548 KB Output is correct
14 Correct 2 ms 1368 KB Output is correct
15 Correct 3 ms 2004 KB Output is correct
16 Correct 2 ms 1112 KB Output is correct
17 Correct 2 ms 1300 KB Output is correct
18 Correct 3 ms 2200 KB Output is correct
19 Correct 3 ms 1080 KB Output is correct
20 Correct 4 ms 1624 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 3 ms 1056 KB Output is correct
3 Correct 2 ms 860 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 1 ms 600 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 796 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 3 ms 1052 KB Output is correct
10 Correct 3 ms 1052 KB Output is correct
11 Correct 3 ms 1052 KB Output is correct
12 Correct 4 ms 1368 KB Output is correct
13 Correct 6 ms 1548 KB Output is correct
14 Correct 2 ms 1368 KB Output is correct
15 Correct 3 ms 2004 KB Output is correct
16 Correct 2 ms 1112 KB Output is correct
17 Correct 2 ms 1300 KB Output is correct
18 Correct 3 ms 2200 KB Output is correct
19 Correct 3 ms 1080 KB Output is correct
20 Correct 4 ms 1624 KB Output is correct
21 Correct 10 ms 3428 KB Output is correct
22 Correct 18 ms 4948 KB Output is correct
23 Correct 18 ms 6344 KB Output is correct
24 Correct 39 ms 8140 KB Output is correct
25 Correct 11 ms 9028 KB Output is correct
26 Correct 23 ms 9168 KB Output is correct
27 Correct 19 ms 6440 KB Output is correct
28 Correct 15 ms 7884 KB Output is correct
29 Correct 19 ms 9892 KB Output is correct
30 Correct 30 ms 7628 KB Output is correct

Subtask #5
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 3 ms 1056 KB Output is correct
3 Correct 2 ms 860 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 1 ms 600 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 796 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 3 ms 1052 KB Output is correct
10 Correct 3 ms 1052 KB Output is correct
11 Correct 161 ms 39848 KB Output is correct
12 Correct 725 ms 92408 KB Output is correct
13 Correct 175 ms 83884 KB Output is correct
14 Correct 503 ms 77112 KB Output is correct
15 Correct 480 ms 76396 KB Output is correct
16 Correct 522 ms 74612 KB Output is correct
17 Correct 187 ms 83580 KB Output is correct
18 Correct 1281 ms 118264 KB Output is correct
19 Correct 1520 ms 126248 KB Output is correct
20 Correct 346 ms 74416 KB Output is correct
21 Correct 3 ms 1052 KB Output is correct
22 Correct 4 ms 1368 KB Output is correct
23 Correct 6 ms 1548 KB Output is correct
24 Correct 2 ms 1368 KB Output is correct
25 Correct 3 ms 2004 KB Output is correct
26 Correct 2 ms 1112 KB Output is correct
27 Correct 2 ms 1300 KB Output is correct
28 Correct 3 ms 2200 KB Output is correct
29 Correct 3 ms 1080 KB Output is correct
30 Correct 4 ms 1624 KB Output is correct
31 Correct 10 ms 3428 KB Output is correct
32 Correct 18 ms 4948 KB Output is correct
33 Correct 18 ms 6344 KB Output is correct
34 Correct 39 ms 8140 KB Output is correct
35 Correct 11 ms 9028 KB Output is correct
36 Correct 23 ms 9168 KB Output is correct
37 Correct 19 ms 6440 KB Output is correct
38 Correct 15 ms 7884 KB Output is correct
39 Correct 19 ms 9892 KB Output is correct
40 Correct 30 ms 7628 KB Output is correct
41 Correct 103 ms 28332 KB Output is correct
42 Correct 509 ms 89420 KB Output is correct
43 Correct 158 ms 76872 KB Output is correct
44 Correct 178 ms 77180 KB Output is correct
45 Correct 303 ms 94436 KB Output is correct
46 Correct 314 ms 65192 KB Output is correct
47 Correct 409 ms 66180 KB Output is correct
48 Correct 173 ms 83884 KB Output is correct
49 Correct 319 ms 68020 KB Output is correct
50 Correct 320 ms 66732 KB Output is correct
51 Correct 177 ms 66704 KB Output is correct
52 Correct 145 ms 64936 KB Output is correct
53 Correct 180 ms 90708 KB Output is correct
54 Correct 967 ms 98680 KB Output is correct
55 Correct 629 ms 79492 KB Output is correct