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답안 #525866

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
525866 2022-02-13T04:13:56 Z mjhmjh1104 Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 852 ms 29200 KB 
#include <set>
#include <cstdio>
#include <vector>
#include <utility>
#include <iterator>
#include <algorithm>
using namespace std;
 
int n, m;
vector<int> tree[200006], child[200006];
vector<pair<int, int>> adj[200006];
int _par[200006], _sz[200006];
int sz[200006], depth[200006], par[200006];
int in[200006], top[100006], T;
int sp[18][200006];
multiset<int> lt_depth[200006];
int max_depth[200006], rev_max_depth[200006], dist[200006], rev_dist[200006];
int edge[200006];
 
int dfs(int x, int prev = -1) {
    _par[x] = prev;
    _sz[x] = 1;
    for (auto &i: tree[x]) if (i != prev) {
        _sz[x] = max(_sz[x], dfs(i, x) + 1);
    }
    return _sz[x];
}
 
int dfs_dist(int x) {
    vector<int> v;
    max_depth[x] = 0;
    dist[x] = 0;
    for (auto &i: child[x]) {
        v.push_back(dfs_dist(i) + 1);
        max_depth[x] = max(max_depth[x], v.back());
        dist[x] = max(dist[x], dist[i]);
    }
    int v0 = max_element(v.begin(), v.end()) - v.begin();
    int X = v[v0];
    if (!v.empty()) v[v0] = 0;
    int v1 = max_element(v.begin(), v.end()) - v.begin();
    v[v0] = X;
    if (!v.empty()) dist[x] = max(dist[x], v[v0]);
    if ((int)v.size() > 1) dist[x] = max(dist[x], v[v0] + v[v1]);
    return max_depth[x];
}

void dfs_rev_dist(int x) {
    multiset<int> v, u, w;
    if (par[x] != -1) {
        v.insert(rev_max_depth[x]);
        u.insert(rev_dist[x]);
    }
    for (auto &i: child[x]) {
        v.insert(max_depth[i] + 1);
        u.insert(dist[i]);
    }
    for (auto &i: child[x]) {
        v.erase(v.find(max_depth[i] + 1));
        u.erase(u.find(dist[i]));
        if (!u.empty()) rev_dist[i] = *u.rbegin();
        if (!v.empty()) rev_dist[i] = max(rev_dist[i], rev_max_depth[i] = *v.rbegin() + 1);
        if ((int)v.size() > 1) rev_dist[i] = max(rev_dist[i], *v.rbegin() + *prev(prev(v.end())));
        v.insert(max_depth[i] + 1);
        u.insert(dist[i]);
    }
    for (auto &i: child[x]) dfs_rev_dist(i);
}

void dfs_edge(int x) {
    multiset<int> v;
    for (auto &i: child[x]) v.insert(max_depth[i] + 1);
    for (auto &i: child[x]) {
        v.erase(v.find(max_depth[i] + 1));
        if ((int)v.size() > 1) edge[i] = *v.rbegin() + *prev(prev(v.end()));
        else if (!v.empty()) edge[i] = *v.rbegin();
        v.insert(max_depth[i] + 1);
    }
    for (auto &i: child[x]) dfs_edge(i);
}

void dfs_child(int x, int prev = -1) {
    par[x] = prev;
    for (auto &i: tree[x]) if (i != prev) {
        child[x].push_back(i);
        dfs_child(i, x);
    }
}

int dfs_sz(int x) {
    sz[x] = 1;
    for (auto &i: child[x]) {
        depth[i] = depth[x] + 1;
        sz[x] += dfs_sz(i);
        if (sz[i] > sz[child[x][0]]) swap(child[x][0], i);
    }
    return sz[x];
}

void dfs_hld(int x) {
    in[x] = T++;
    for (auto &i: child[x]) {
        top[i] = (i == child[x][0] ? top[x] : i);
        dfs_hld(i);
    }
}

int lca(int u, int v) {
    int ret = 0;
    while (top[u] != top[v]) {
        if (depth[top[u]] < depth[top[v]]) swap(u, v);
        ret += depth[u] - depth[par[top[u]]];
        u = par[top[u]];
    }
    if (depth[u] > depth[v]) swap(u, v);
    return u;
}

int pr(int x, int y) {
    for (int t = 17; t >= 0; t--) if (y >= 1 << t) {
        y -= 1 << t;
        x = sp[t][x];
    }
    return x;
}

int tree_dist[524288], tree_edge[524288];

int query_dist(int i, int b, int e, int l, int r) {
    if (r < l || r < b || e < l) return 0;
    if (l <= b && e <= r) return tree_dist[i];
    int m = (b + e) / 2;
    return max(query_dist(i * 2 + 1, b, m, l, r), query_dist(i * 2 + 2, m + 1, e, l, r));
}

int query_edge(int i, int b, int e, int l, int r) {
    if (r < l || r < b || e < l) return 0;
    if (l <= b && e <= r) return tree_edge[i];
    int m = (b + e) / 2;
    return max(query_edge(i * 2 + 1, b, m, l, r), query_edge(i * 2 + 2, m + 1, e, l, r));
}

vector<pair<int, int>> lt;

void query_hld(int u, int v) {
    while (top[u] != top[v]) {
        if (depth[top[u]] < depth[top[v]]) swap(u, v);
        lt.push_back({ in[top[u]], in[u] });
        u = par[top[u]];
    }
    lt.push_back({ min(in[u], in[v]), max(in[u], in[v]) });
}

int query_hld_dist(int u, int v, int x, int y) {
    lt.clear();
    query_hld(u, v);
    sort(lt.begin(), lt.end());
    int ret = max(query_dist(0, 0, 262143, x, lt[0].first - 1), query_dist(0, 0, 262143, lt.back().second + 1, y));
    for (int i = 1; i < (int)lt.size(); i++) ret = max(ret, query_dist(0, 0, 262143, lt[i - 1].second + 1, lt[i].first - 1));
    return ret;
}

int query_hld_edge(int u, int v) {
    int ret = 0;
    while (top[u] != top[v]) {
        if (depth[top[u]] < depth[top[v]]) swap(u, v);
        ret = max(ret, query_edge(0, 0, 262143, in[top[u]], in[u]));
        u = par[top[u]];
    }
    ret = max(ret, query_edge(0, 0, 262143, min(in[u], in[v]), max(in[u], in[v])));
    return ret;
}

int main() {
    scanf("%d%d", &n, &m);
    while (m--) {
        int x, y, w;
        scanf("%d%d%d", &x, &y, &w);
        if (w == 1) {
            tree[x].push_back(y);
            tree[y].push_back(x);
        } else {
            adj[x].push_back({ y, w });
            adj[y].push_back({ x, w });
        }
    }
    dfs_child(0);
    dfs_sz(0);
    dfs_hld(0);
    dfs_dist(0);
    dfs_rev_dist(0);
    dfs_edge(0);
    for (int i = 0; i < n; i++) sp[0][i] = par[i];
    for (int t = 1; t < 18; t++) for (int i = 0; i < n; i++) {
        if (sp[t - 1][i] == -1) sp[t][i] = -1;
        else sp[t][i] = sp[t - 1][sp[t - 1][i]];
    }
    for (int i = 0; i < n; i++) {
        tree_dist[262143 + in[i]] = dist[i];
        tree_edge[262143 + in[i]] = edge[i];
    }
    for (int i = 262142; i >= 0; i--) {
        tree_dist[i] = max(tree_dist[i * 2 + 1], tree_dist[i * 2 + 2]);
        tree_edge[i] = max(tree_edge[i * 2 + 1], tree_edge[i * 2 + 2]);
    }
    for (int i = 0; i < n; i++) for (auto &j: child[i]) lt_depth[i].insert(max_depth[j] + 1);
    int zero = 2 * (n - 1) - dist[0], one = (int)1e9;
    for (int i = 0; i < n; i++) {
        dfs(i);
        for (auto &j: adj[i]) if (i < j.first) {
            int l = lca(i, j.first);
            int ds = depth[i] + depth[j.first] - depth[l] - depth[l];
            int curr = j.second + 2 * (n - 1) - ds - 1;
            int x = j.first, pv = -1;
            vector<pair<int, int>> v;
            int y = max(rev_dist[l] - 1, query_hld_dist(i, j.first, in[l], in[l] + sz[l] - 1) - 1), T = 0;
            int A = (i == l ? -1 : pr(i, depth[i] - depth[l] - 1));
            int B = (j.first == l ? -1 : pr(j.first, depth[j.first] - depth[l] - 1));
            int Ap = (depth[i] - depth[l] - 2 >= 0 ? pr(i, depth[i] - depth[l] - 2) : -1);
            int Bp = (depth[j.first] - depth[l] - 2 >= 0 ? pr(j.first, depth[j.first] - depth[l] - 2) : -1);
            {
                if (A != -1) lt_depth[l].erase(lt_depth[l].find(max_depth[A] + 1));
                if (B != -1) lt_depth[l].erase(lt_depth[l].find(max_depth[B] + 1));
                if (!lt_depth[l].empty()) y = max(y, *lt_depth[l].rbegin() + rev_max_depth[l]);
                else y = max(y, rev_max_depth[l]);
                if ((int)lt_depth[l].size() > 1) y = max(y, *lt_depth[l].rbegin() + *prev(prev(lt_depth[l].end())) - 1);
                if (A != -1) lt_depth[l].insert(max_depth[A] + 1);
                if (B != -1) lt_depth[l].insert(max_depth[B] + 1);
            }
            if (Ap != -1) y = max(y, query_hld_edge(Ap, i) - 1);
            if (Bp != -1) y = max(y, query_hld_edge(Bp, j.first) - 1);
            while (x != -1) {
                for (auto &k: tree[x]) if (k != pv && k != _par[x]) {
                    if (_sz[k]) {
                        if (!v.empty() && v.back().second == T) {
                            //y = max(y, v.back().first + _sz[k] - 1);
                            v.back().first = max(v.back().first, _sz[k]);
                        } else v.push_back({ _sz[k], T });
                    }
                }
                T++;
                pv = x;
                x = _par[x];
            }
            int ans = -(int)1e9;
            for (int i = 0; i < (int)v.size(); i++) {
                if (i) ans -= v[i].second - v[i - 1].second;
                y = max(y, ans + v[i].first + 1);
                ans = max(ans, v[i].first);
            }
            curr -= y;
            one = min(one, curr);
        }
    }
    printf("%d", min(zero, one));
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:175:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  175 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp:178:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  178 |         scanf("%d%d%d", &x, &y, &w);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
1.0 / 1.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct

Subtask #2
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct
16 Correct 12 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Correct 12 ms 25932 KB Output is correct
19 Correct 12 ms 25916 KB Output is correct
20 Correct 12 ms 25932 KB Output is correct
21 Correct 12 ms 25932 KB Output is correct
22 Correct 12 ms 25932 KB Output is correct
23 Correct 12 ms 26004 KB Output is correct
24 Correct 13 ms 26004 KB Output is correct
25 Incorrect 13 ms 25932 KB Output isn't correct
26 Halted 0 ms 0 KB -

Subtask #3
2.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 757 ms 28868 KB Output is correct
2 Correct 822 ms 29200 KB Output is correct
3 Correct 772 ms 28288 KB Output is correct
4 Correct 667 ms 27884 KB Output is correct
5 Correct 645 ms 27764 KB Output is correct
6 Correct 288 ms 27440 KB Output is correct
7 Correct 767 ms 28876 KB Output is correct
8 Correct 852 ms 28388 KB Output is correct
9 Correct 838 ms 29016 KB Output is correct
10 Correct 645 ms 27724 KB Output is correct
11 Correct 639 ms 28424 KB Output is correct
12 Correct 685 ms 27624 KB Output is correct
13 Correct 685 ms 28104 KB Output is correct
14 Correct 657 ms 28176 KB Output is correct

Subtask #4
0.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct
16 Correct 12 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Correct 12 ms 25932 KB Output is correct
19 Correct 12 ms 25916 KB Output is correct
20 Correct 12 ms 25932 KB Output is correct
21 Correct 12 ms 25932 KB Output is correct
22 Correct 12 ms 25932 KB Output is correct
23 Correct 12 ms 26004 KB Output is correct
24 Correct 13 ms 26004 KB Output is correct
25 Incorrect 13 ms 25932 KB Output isn't correct
26 Halted 0 ms 0 KB -

Subtask #5
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct
16 Correct 12 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Correct 12 ms 25932 KB Output is correct
19 Correct 12 ms 25916 KB Output is correct
20 Correct 12 ms 25932 KB Output is correct
21 Correct 12 ms 25932 KB Output is correct
22 Correct 12 ms 25932 KB Output is correct
23 Correct 12 ms 26004 KB Output is correct
24 Correct 13 ms 26004 KB Output is correct
25 Incorrect 13 ms 25932 KB Output isn't correct
26 Halted 0 ms 0 KB -

Subtask #6
0.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct
16 Correct 12 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Correct 12 ms 25932 KB Output is correct
19 Correct 12 ms 25916 KB Output is correct
20 Correct 12 ms 25932 KB Output is correct
21 Correct 12 ms 25932 KB Output is correct
22 Correct 12 ms 25932 KB Output is correct
23 Correct 12 ms 26004 KB Output is correct
24 Correct 13 ms 26004 KB Output is correct
25 Incorrect 13 ms 25932 KB Output isn't correct
26 Halted 0 ms 0 KB -

Subtask #7
0.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct
16 Correct 12 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Correct 12 ms 25932 KB Output is correct
19 Correct 12 ms 25916 KB Output is correct
20 Correct 12 ms 25932 KB Output is correct
21 Correct 12 ms 25932 KB Output is correct
22 Correct 12 ms 25932 KB Output is correct
23 Correct 12 ms 26004 KB Output is correct
24 Correct 13 ms 26004 KB Output is correct
25 Incorrect 13 ms 25932 KB Output isn't correct
26 Halted 0 ms 0 KB -

Subtask #8
0.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 25932 KB Output is correct
2 Correct 15 ms 25996 KB Output is correct
3 Correct 13 ms 25932 KB Output is correct
4 Correct 13 ms 25988 KB Output is correct
5 Correct 12 ms 25944 KB Output is correct
6 Correct 13 ms 25944 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 13 ms 25916 KB Output is correct
9 Correct 13 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 13 ms 25924 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 14 ms 25888 KB Output is correct
16 Correct 12 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Correct 12 ms 25932 KB Output is correct
19 Correct 12 ms 25916 KB Output is correct
20 Correct 12 ms 25932 KB Output is correct
21 Correct 12 ms 25932 KB Output is correct
22 Correct 12 ms 25932 KB Output is correct
23 Correct 12 ms 26004 KB Output is correct
24 Correct 13 ms 26004 KB Output is correct
25 Incorrect 13 ms 25932 KB Output isn't correct
26 Halted 0 ms 0 KB -