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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#415610#6559. A Tree and Two Edgesngpin04#WA 1499ms8880kbC++145.7kb2024-05-21 05:42:232024-05-21 05:42:23

Judging History

你现在查看的是最新测评结果

  • [2024-05-21 05:42:23]
  • 评测
  • 测评结果:WA
  • 用时:1499ms
  • 内存:8880kb
  • [2024-05-21 05:42:23]
  • 提交

answer

#include <bits/stdc++.h>
#define fi first 
#define se second
#define mp make_pair
#define lb lower_bound
#define pb push_back
#define bit(n) (1LL << (n))
#define getbit(x, i) (((x) >> (i)) & 1)
#define pii pair <int, int>
#define ALL(x) x.begin(), x.end()
using namespace std;
const int oo = 1e9;
const long long ooo = 1e18;

template<typename T1, typename T2> bool mini(T1 &a, T2 b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<typename T1, typename T2> bool maxi(T1 &a, T2 b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
const int lim = 5e4 + 5;
struct disjoint_set {
    int h[lim], sz[lim];
    disjoint_set() {
        memset(h, -1, sizeof(h));
        fill(sz, sz + lim, 1);
    }
    int fh(int nd) {
        return h[nd] == -1 ? nd : h[nd] = fh(h[nd]);
    }
    bool same_par(int x, int y) {
        return fh(x) == fh(y);
    }
    bool merge(int x, int y) {
        x = fh(x), y = fh(y);
        if(x != y) {
            if(sz[x] < sz[y])
                swap(x, y);
            sz[x] += sz[y];
            h[y] = x;
        }
        return x != y;
    }
};
vector<int> edges[lim];
int disc[lim], low[lim], t;
vector<pair<int, int>> bridges;
void tarjan(int nd, int pr = -1) {
    disc[nd] = low[nd] = t++;
    for(auto x : edges[nd]) {
        if(x == pr)
            continue;
        if(disc[x] == -1) {
            tarjan(x, nd);
            low[nd] = min(low[nd], low[x]);
        }
        else {
            low[nd] = min(low[nd], disc[x]);
        }
        if(low[x] > disc[nd])   
            bridges.pb(mp(nd, x));
    }   
}
bool vis[lim];
void dfs(int nd, int origin, vector<pair<int, int>> &a) {
    vis[nd] = 1;
    a.pb(mp(nd, origin));
    for(auto i : edges[nd]) {
        if(!vis[i]) {
            dfs(i, origin, a);
        }
    }

}
int main() {
    memset(disc, -1, sizeof(disc));
    memset(low, -1, sizeof(low));
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, q;
    cin >> n >> q;
    vector<pair<int, int>> adj;
    for(int i = 1; i <= n + 1; ++i) {
        int u, v;
        cin >> u >> v;
        edges[u].pb(v);
        edges[v].pb(u);
        adj.pb(mp(u, v));
    }
    tarjan(1);
    // cerr << "bridge cnt: " << bridges.size() << endl;
    for(auto &p : bridges) {
        if(p.fi > p.se)
            swap(p.fi, p.se);
        // cerr << p.fi << " " << p.se << endl;
    }
    sort(bridges.begin(), bridges.end());
    disjoint_set dsu;
    for(auto p : adj) {
        if(p.fi > p.se)
            swap(p.fi, p.se);
        if(!binary_search(bridges.begin(), bridges.end(), p)) {
            // not bridge
            dsu.merge(p.fi, p.se);
        }
    }
    // nbd -> non bridge degree
    int nbd[n + 1];
    memset(nbd, 0, sizeof(nbd));
    // cerr << "nbd" << endl;
    for(int i = 1; i <= n; ++i) {
        for(auto x : edges[i]) {
            if(dsu.same_par(i, x)) {
                ++nbd[i];
            }
        }
        // cerr << nbd[i] << " ";
    }
    // cerr << endl;
    for(int i = 1; i <= n; ++i)
        edges[i].clear();
    for(auto p : adj) {
        if(p.fi > p.se)
            swap(p.fi, p.se);
        if(binary_search(bridges.begin(), bridges.end(), p)) {
            // bridge
            edges[p.fi].pb(p.se);
            edges[p.se].pb(p.fi);
        }
    }
    // fi -> node to find
    // se -> last node in the important cc
    vector<vector<pair<int, int>>> v;
    bool used[n + 1];
    memset(used, 0, sizeof(used));
    for(int i = 1; i <= n; ++i) {
        // cerr << dsu.fh(i) << " " << dsu.sz[dsu.fh(i)] << endl;
        if(dsu.sz[dsu.fh(i)] > 1 && !used[dsu.fh(i)]) {
            // cerr << "dfs " << i << endl;
            vector<pair<int, int>> cur;
            used[dsu.fh(i)] = 1;
            // find for every other node the original
            memset(vis, 0, sizeof(vis));
            for(int j = 1; j <= n; ++j) {
                if(dsu.fh(j) == dsu.fh(i))
                    dfs(j, j, cur);
            }
            sort(cur.begin(), cur.end());
            v.pb(cur);
        }
    }
    for(int i = 1; i <= n; ++i) {
        if(nbd[i] == 4) {
            // special special case
            int spec = i;
            disjoint_set dsu;
            for(auto p : adj) {
                if(p.fi != i && p.se != i)
                    dsu.merge(p.fi, p.se);
            }
            while(q--) {
                int x, y;
                cin >> x >> y;
                int res = 1;
                for(auto vec : v) {
                    int ndx = (*lb(vec.begin(), vec.end(), mp(x, 0))).se, ndy = (*lb(vec.begin(), vec.end(), mp(y, 0))).se;
                    // cerr << x << " " << y << " " << ndx << " " << ndy << endl;
                    if(ndx == ndy)
                        res *= 1;
                    else if(nbd[ndx] == 4 || nbd[ndy] == 4 || dsu.same_par(x, y)) 
                        res *= 2;
                    else
                        res *= 4;
                }
                cout << res << endl;
            }
            exit(0);
        }
    }
    while(q--) {
        int x, y;
        cin >> x >> y;
        int res = 1;
        for(auto vec : v) {
            int ndx = (*lb(vec.begin(), vec.end(), mp(x, 0))).se, ndy = (*lb(vec.begin(), vec.end(), mp(y, 0))).se;
            // cerr << ndx << " " << ndy << endl;
            if(ndx == ndy)
                res *= 1;
            else if(nbd[ndx] == 3 || nbd[ndy] == 3)
                res *= 3;
            else if(v.size() == 1)
                res *= 4;
            else
                res *= 2;
        }
        cout << res << endl;
    }
    return 0;
}

详细

Test #1:

score: 100
Accepted
time: 2ms
memory: 6052kb

input:

4 6
1 2
1 3
1 4
2 3
2 4
1 2
1 3
1 4
2 3
2 4
3 4

output:

3
3
3
3
3
4

result:

ok 6 lines

Test #2:

score: 0
Accepted
time: 2ms
memory: 5896kb

input:

6 4
1 2
1 3
1 6
2 3
3 4
3 5
4 5
1 2
1 3
1 4
1 6

output:

2
2
4
1

result:

ok 4 lines

Test #3:

score: -100
Wrong Answer
time: 1499ms
memory: 8880kb

input:

50000 50000
11561 23122
14261 28523
24407 48814
17947 35894
14803 29607
19557 39115
12415 24830
9583 19167
18397 36794
439 878
18040 36080
17150 34300
7922 15845
18938 37877
18625 37250
6459 12919
9818 19636
3579 7158
21323 42646
23882 47764
13603 27207
8353 16707
15907 31814
20935 41871
11686 23372...

output:

4
4
4
4
4
4
1
4
4
1
4
4
4
4
4
4
1
4
4
4
4
4
4
4
4
4
4
4
4
4
1
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
1
4
1
1
4
4
4
4
4
4
1
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
1
4
4
4
4
4
4
4
4
4
4
1
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
1
4
4
4
4
4
4
4
...

result:

wrong answer 2nd lines differ - expected: '3', found: '4'