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답안 #525863

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
525863 2022-02-13T04:09:29 Z mjhmjh1104 Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 859 ms 29192 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]);
    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]));
                if (B != -1) lt_depth[l].erase(lt_depth[l].find(max_depth[B]));
                if (!lt_depth[l].empty()) y = max(y, *lt_depth[l].rbegin() + rev_max_depth[l] - 1);
                else y = max(y, rev_max_depth[l] - 1);
                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]);
                if (B != -1) lt_depth[l].insert(max_depth[B]);
            }
            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) {
                            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 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct

Subtask #2
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct
16 Correct 13 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25932 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #3
2.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 804 ms 28772 KB Output is correct
2 Correct 812 ms 29192 KB Output is correct
3 Correct 806 ms 28276 KB Output is correct
4 Correct 697 ms 27876 KB Output is correct
5 Correct 677 ms 27768 KB Output is correct
6 Correct 307 ms 27332 KB Output is correct
7 Correct 859 ms 28972 KB Output is correct
8 Correct 851 ms 28388 KB Output is correct
9 Correct 805 ms 28976 KB Output is correct
10 Correct 661 ms 27804 KB Output is correct
11 Correct 679 ms 28424 KB Output is correct
12 Correct 695 ms 27640 KB Output is correct
13 Correct 673 ms 28108 KB Output is correct
14 Correct 695 ms 28168 KB Output is correct

Subtask #4
0.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct
16 Correct 13 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25932 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #5
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct
16 Correct 13 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25932 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #6
0.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct
16 Correct 13 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25932 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #7
0.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct
16 Correct 13 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25932 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25980 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 15 ms 26032 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25932 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 12 ms 25932 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25980 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25996 KB Output is correct
14 Correct 12 ms 25996 KB Output is correct
15 Correct 13 ms 25968 KB Output is correct
16 Correct 13 ms 25932 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25932 KB Output isn't correct
19 Halted 0 ms 0 KB -