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Submission #525845

# Submission time Handle Problem Language Result Execution time Memory
525845 2022-02-13T03:24:02 Z mjhmjh1104 Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 839 ms 29184 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]);
    for (auto &i: child[x]) {
        v.erase(v.find(max_depth[i]));
        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]);
    }
    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]);
                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

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct

Subtask #2
0.0 / 2.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct
16 Correct 12 ms 25940 KB Output is correct
17 Correct 12 ms 26000 KB Output is correct
18 Incorrect 12 ms 25888 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #3
2.0 / 2.0

# Verdict Execution time Memory Grader output
1 Correct 799 ms 28768 KB Output is correct
2 Correct 839 ms 29184 KB Output is correct
3 Correct 762 ms 28276 KB Output is correct
4 Correct 666 ms 27972 KB Output is correct
5 Correct 651 ms 27844 KB Output is correct
6 Correct 284 ms 27420 KB Output is correct
7 Correct 813 ms 28972 KB Output is correct
8 Correct 814 ms 28396 KB Output is correct
9 Correct 801 ms 28996 KB Output is correct
10 Correct 655 ms 27812 KB Output is correct
11 Correct 656 ms 28420 KB Output is correct
12 Correct 691 ms 27696 KB Output is correct
13 Correct 689 ms 28100 KB Output is correct
14 Correct 610 ms 28172 KB Output is correct

Subtask #4
0.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct
16 Correct 12 ms 25940 KB Output is correct
17 Correct 12 ms 26000 KB Output is correct
18 Incorrect 12 ms 25888 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #5
0.0 / 2.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct
16 Correct 12 ms 25940 KB Output is correct
17 Correct 12 ms 26000 KB Output is correct
18 Incorrect 12 ms 25888 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #6
0.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct
16 Correct 12 ms 25940 KB Output is correct
17 Correct 12 ms 26000 KB Output is correct
18 Incorrect 12 ms 25888 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #7
0.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct
16 Correct 12 ms 25940 KB Output is correct
17 Correct 12 ms 26000 KB Output is correct
18 Incorrect 12 ms 25888 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 12 ms 25892 KB Output is correct
3 Correct 12 ms 25932 KB Output is correct
4 Correct 13 ms 25948 KB Output is correct
5 Correct 13 ms 25932 KB Output is correct
6 Correct 12 ms 25932 KB Output is correct
7 Correct 12 ms 25896 KB Output is correct
8 Correct 12 ms 25932 KB Output is correct
9 Correct 13 ms 25884 KB Output is correct
10 Correct 12 ms 25932 KB Output is correct
11 Correct 12 ms 25932 KB Output is correct
12 Correct 12 ms 25932 KB Output is correct
13 Correct 12 ms 25912 KB Output is correct
14 Correct 12 ms 25932 KB Output is correct
15 Correct 12 ms 25884 KB Output is correct
16 Correct 12 ms 25940 KB Output is correct
17 Correct 12 ms 26000 KB Output is correct
18 Incorrect 12 ms 25888 KB Output isn't correct
19 Halted 0 ms 0 KB -