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Submission #526147

# Submission time Handle Problem Language Result Execution time Memory
526147 2022-02-13T20:20:21 Z mjhmjh1104 Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 108 ms 184936 KB 
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#include <set>
#include <tuple>
#include <cstdio>
#include <vector>
#include <utility>
#include <iterator>
#include <algorithm>
using namespace std;

struct Item {
    int posde;
    int negde;
    int ans;
    Item (): posde((int)-1e9), negde((int)-1e9), ans((int)-1e9) {}
    Item (int posde, int negde, int ans): posde(posde), negde(negde), ans(ans) {}
} sp_split[19][500006];

int n, m;
vector<int> tree[500006], child[500006];
vector<tuple<int, int, int>> adj;
int depth[500006], sp[19][500006], sp_dist[19][500006];
multiset<int> lt_depth[500006], lt_dist[500006];
int max_depth[500006], rev_max_depth[500006], dist[500006], rev_dist[500006];
int prev_dist[500006], prev_depth[500006][2];

Item query_sp_res(int A, int x) {
    if (A == -1) return Item();
    Item ret = { prev_depth[x][0] + depth[x], prev_depth[x][0] - depth[x], (int)-1e9 };
    if (A == x) return ret;
    for (int t = 18; t >= 0; t--) if (sp[t][x] != -1 && depth[sp[t][x]] > depth[A]) {
        ret.ans = max({ sp_split[t][x].ans, ret.ans, sp_split[t][x].posde + ret.negde });
        ret.posde = max(sp_split[t][x].posde, ret.posde);
        ret.negde = max(sp_split[t][x].negde, ret.negde);
        x = sp[t][x];
    }
    ret.ans = max({ sp_split[0][x].ans, ret.ans, sp_split[0][x].posde + ret.negde });
    ret.posde = max(sp_split[0][x].posde, ret.posde);
    ret.negde = max(sp_split[0][x].negde, ret.negde);
    return ret;
}

int dfs_dist(int x) {
    max_depth[x] = 0;
    dist[x] = 0;
    int mx0 = (int)-1e9, mx1 = (int)-1e9;
    for (auto &i: child[x]) {
        int t = dfs_dist(i) + 1;
        max_depth[x] = max(max_depth[x], t);
        if (t > mx0) mx1 = mx0, mx0 = t;
        else if (t > mx1) mx1 = t;
        dist[x] = max(dist[x], dist[i]);
    }
    dist[x] = max(dist[x], mx0 + max(mx1, 0));
    return max_depth[x];
}

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


void dfs_f_dist(int x) {
    for (auto &i: child[x]) {
        lt_dist[x].erase(lt_dist[x].find(dist[i]));
        sp_dist[0][i] = (lt_dist[x].empty() ? 0 : *lt_dist[x].rbegin());
        lt_dist[x].insert(dist[i]);
    }
    for (auto &i: child[x]) dfs_f_dist(i);
}

void dfs_edge(int x) {
    for (auto &i: child[x]) {
        lt_depth[x].erase(lt_depth[x].find(max_depth[i] + 1));
        if ((int)lt_depth[x].size() > 1) sp_dist[0][i] = max(sp_dist[0][i], *lt_depth[x].rbegin() + *prev(prev(lt_depth[x].end())));
        else if (!lt_depth[x].empty()) sp_dist[0][i] = max(sp_dist[0][i], *lt_depth[x].rbegin());
        int V = (lt_depth[x].empty() ? 0 : *lt_depth[x].rbegin());
        sp_split[0][i].posde = V + depth[x];
        sp_split[0][i].negde = V - depth[x];
        lt_depth[x].insert(max_depth[i] + 1);
    }
    for (auto &i: child[x]) dfs_edge(i);
}

void dfs_child(int x, int prev = -1) {
    sp[0][x] = prev;
    for (auto &i: tree[x]) if (i != prev) {
        depth[i] = depth[x] + 1;
        child[x].push_back(i);
        dfs_child(i, x);
    }
}

int A, B;

int lca(int u, int v) {
    bool sw = false;
    if (depth[u] < depth[v]) swap(u, v), sw = true;
    int diff = depth[u] - depth[v];
    for (int t = 18; t >= 0; t--) if (diff >= 1 << t) {
        diff -= 1 << t;
        u = sp[t][u];
    }
    if (u == v) return u;
    for (int t = 18; t >= 0; t--) if (sp[t][u] != -1 && sp[t][v] != -1 && sp[t][u] != sp[t][v]) {
        u = sp[t][u];
        v = sp[t][v];
    }
    A = u, B = v;
    if (sw) swap(A, B);
    return sp[0][u];
}

int pr(int x, int y) {
    for (int t = 18; t >= 0; t--) if (y >= 1 << t) {
        y -= 1 << t;
        x = sp[t][x];
    }
    return x;
}

int query_sp_dist(int u, int v, int l, int A, int B) {
    int ret = 0;
    if (u != l) {
        ret = max(prev_depth[u][1], prev_dist[u]);
        u = sp[0][u];
    }
    if (v != l) {
        ret = max(prev_depth[v][1], prev_dist[v]);
        v = sp[0][v];
    }
    for (int t = 18; t >= 0; t--) if (sp[t][u] != -1 && depth[sp[t][u]] > depth[l]) {
        ret = max(ret, sp_dist[t][u]);
        u = sp[t][u];
    }
    for (int t = 18; t >= 0; t--) if (sp[t][v] != -1 && depth[sp[t][v]] > depth[l]) {
        ret = max(ret, sp_dist[t][v]);
        v = sp[t][v];
    }
    if (A != -1) lt_dist[l].erase(lt_dist[l].find(dist[A]));
    if (B != -1) lt_dist[l].erase(lt_dist[l].find(dist[B]));
    ret = max(ret, lt_dist[l].empty() ? 0 : *lt_dist[l].rbegin());
    if (A != -1) lt_dist[l].insert(dist[A]);
    if (B != -1) lt_dist[l].insert(dist[B]);
    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.push_back({ x, y, w });
    }
    dfs_child(0);
    dfs_dist(0);
    dfs_rev_dist(0);
    for (int i = 0; i < n; i++) {
        prev_dist[i] = (lt_dist[i].empty() ? (int)-1e9 : *lt_dist[i].rbegin());
        prev_depth[i][0] = (lt_depth[i].empty() ? (int)-1e9 : *lt_depth[i].rbegin());
        prev_depth[i][1] = ((int)lt_depth[i].size() < 2 ? (int)-1e9 : prev_depth[i][0] + *next(lt_depth[i].rbegin()));
    }
    dfs_f_dist(0);
    dfs_edge(0);
    for (int t = 1; t < 19; t++) for (int i = 0; i < n; i++) {
        if (sp[t - 1][i] == -1) {
            sp[t][i] = -1;
            sp_dist[t][i] = sp_dist[t - 1][i];
            sp_split[t][i] = sp_split[t - 1][i];
        } else {
            sp[t][i] = sp[t - 1][sp[t - 1][i]];
            sp_dist[t][i] = max(sp_dist[t - 1][i], sp_dist[t - 1][sp[t - 1][i]]);
            sp_split[t][i].ans = max({ sp_split[t - 1][sp[t - 1][i]].ans, sp_split[t - 1][i].ans, sp_split[t - 1][sp[t - 1][i]].posde + sp_split[t - 1][i].negde });
            sp_split[t][i].posde = max(sp_split[t - 1][sp[t - 1][i]].posde, sp_split[t - 1][i].posde);
            sp_split[t][i].negde = max(sp_split[t - 1][sp[t - 1][i]].negde, sp_split[t - 1][i].negde);
        }
    }
    int res = 2 * (n - 1) - dist[0];
    for (auto [ i, j, w ]: adj) {
        A = B = -1;
        int l = lca(i, j);
        int ds = depth[i] + depth[j] - depth[l] - depth[l];
        int curr = w + 2 * (n - 1) - ds - 1;
        if (A == -1) A = (i == l ? -1 : pr(i, depth[i] - depth[l] - 1));
        if (B == -1) B = (j == l ? -1 : pr(j, depth[j] - depth[l] - 1));
        int G = 0, y = 0;
        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()) G = *lt_depth[l].rbegin();
        else y = max(y, rev_max_depth[l] - 1);
        if ((int)lt_depth[l].size() > 1) y = max(y, G + *next(lt_depth[l].rbegin()) - 1);
        if (A != -1) lt_depth[l].insert(max_depth[A] + 1);
        if (B != -1) lt_depth[l].insert(max_depth[B] + 1);
        Item first = query_sp_res(A, i);
        Item second = query_sp_res(B, j);
        int Alt = first.negde + depth[l];
        int Brt = second.negde + depth[l];
        int Lt = max(rev_max_depth[l], G);
        res = min(res, curr - max({ y, Alt + max(Brt, Lt) + 1, max(Alt, Lt) + Brt + 1, first.ans + 1, second.ans + 1, rev_dist[l] - 1, query_sp_dist(i, j, l, A, B) - 1 }));
    }
    printf("%d", res);
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:169:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  169 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp:172:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  172 |         scanf("%d%d%d", &x, &y, &w);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
1.0 / 1.0

# Verdict Execution time Memory Grader output
1 Correct 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct

Subtask #2
0.0 / 2.0

# Verdict Execution time Memory Grader output
1 Correct 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct
16 Correct 93 ms 182512 KB Output is correct
17 Correct 93 ms 182568 KB Output is correct
18 Incorrect 92 ms 182616 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 105 ms 184896 KB Output is correct
2 Correct 108 ms 184936 KB Output is correct
3 Correct 101 ms 184692 KB Output is correct
4 Correct 103 ms 184512 KB Output is correct
5 Correct 99 ms 184516 KB Output is correct
6 Correct 105 ms 184160 KB Output is correct
7 Correct 106 ms 184772 KB Output is correct
8 Correct 102 ms 184632 KB Output is correct
9 Correct 101 ms 184852 KB Output is correct
10 Correct 102 ms 184552 KB Output is correct
11 Correct 106 ms 184776 KB Output is correct
12 Correct 100 ms 184436 KB Output is correct
13 Correct 102 ms 184556 KB Output is correct
14 Correct 102 ms 184616 KB Output is correct

Subtask #4
0.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct
16 Correct 93 ms 182512 KB Output is correct
17 Correct 93 ms 182568 KB Output is correct
18 Incorrect 92 ms 182616 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 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct
16 Correct 93 ms 182512 KB Output is correct
17 Correct 93 ms 182568 KB Output is correct
18 Incorrect 92 ms 182616 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 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct
16 Correct 93 ms 182512 KB Output is correct
17 Correct 93 ms 182568 KB Output is correct
18 Incorrect 92 ms 182616 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 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct
16 Correct 93 ms 182512 KB Output is correct
17 Correct 93 ms 182568 KB Output is correct
18 Incorrect 92 ms 182616 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 90 ms 182552 KB Output is correct
2 Correct 91 ms 182564 KB Output is correct
3 Correct 92 ms 182540 KB Output is correct
4 Correct 90 ms 182592 KB Output is correct
5 Correct 91 ms 182492 KB Output is correct
6 Correct 91 ms 182548 KB Output is correct
7 Correct 91 ms 182596 KB Output is correct
8 Correct 95 ms 182596 KB Output is correct
9 Correct 92 ms 182580 KB Output is correct
10 Correct 91 ms 182604 KB Output is correct
11 Correct 91 ms 182612 KB Output is correct
12 Correct 91 ms 182540 KB Output is correct
13 Correct 91 ms 182556 KB Output is correct
14 Correct 100 ms 182596 KB Output is correct
15 Correct 92 ms 182592 KB Output is correct
16 Correct 93 ms 182512 KB Output is correct
17 Correct 93 ms 182568 KB Output is correct
18 Incorrect 92 ms 182616 KB Output isn't correct
19 Halted 0 ms 0 KB -