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Submission #525865

# Submission time Handle Problem Language Result Execution time Memory
525865 2022-02-13T04:11:37 Z mjhmjh1104 Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 835 ms 29196 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]);
                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]);
                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) {
                            //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

# Verdict Execution time Memory Grader output
1 Correct 12 ms 25932 KB Output is correct
2 Correct 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 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 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 KB Output is correct
16 Correct 14 ms 25936 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25912 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 767 ms 28768 KB Output is correct
2 Correct 820 ms 29196 KB Output is correct
3 Correct 765 ms 28272 KB Output is correct
4 Correct 591 ms 27888 KB Output is correct
5 Correct 703 ms 27764 KB Output is correct
6 Correct 278 ms 27444 KB Output is correct
7 Correct 835 ms 28972 KB Output is correct
8 Correct 767 ms 28392 KB Output is correct
9 Correct 801 ms 28996 KB Output is correct
10 Correct 640 ms 27804 KB Output is correct
11 Correct 657 ms 28424 KB Output is correct
12 Correct 655 ms 27728 KB Output is correct
13 Correct 674 ms 28108 KB Output is correct
14 Correct 661 ms 28164 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 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 KB Output is correct
16 Correct 14 ms 25936 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25912 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 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 KB Output is correct
16 Correct 14 ms 25936 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25912 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 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 KB Output is correct
16 Correct 14 ms 25936 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25912 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 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 KB Output is correct
16 Correct 14 ms 25936 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25912 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 13 ms 25944 KB Output is correct
3 Correct 13 ms 25956 KB Output is correct
4 Correct 12 ms 25932 KB Output is correct
5 Correct 13 ms 25976 KB Output is correct
6 Correct 13 ms 25908 KB Output is correct
7 Correct 13 ms 25928 KB Output is correct
8 Correct 16 ms 25952 KB Output is correct
9 Correct 16 ms 25996 KB Output is correct
10 Correct 15 ms 25932 KB Output is correct
11 Correct 12 ms 26000 KB Output is correct
12 Correct 13 ms 25932 KB Output is correct
13 Correct 12 ms 25932 KB Output is correct
14 Correct 13 ms 25936 KB Output is correct
15 Correct 17 ms 25972 KB Output is correct
16 Correct 14 ms 25936 KB Output is correct
17 Correct 12 ms 25932 KB Output is correct
18 Incorrect 12 ms 25912 KB Output isn't correct
19 Halted 0 ms 0 KB -