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Submission #761198

# Submission time Handle Problem Language Result Execution time Memory
761198 2023-06-19T10:56:01 Z PanosPask Hard route (IZhO17_road) C++14
100 / 100
 665 ms 136072 KB 
#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define f first
#define s second

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pi;

int N;
vector<vector<int>> adj_list;
vector<ll> d;
vector<ll> c;
pi ans;

void calc_height(int node, int par)
{
    d[node] = 0, c[node] = 1;

    for (auto neigh : adj_list[node]) if (neigh != par){
        calc_height(neigh, node);

        if (d[neigh] + 1 > d[node]) {
            d[node] = d[neigh] + 1;
            c[node] = c[neigh];
        }
        else if (d[neigh] + 1 == d[node]) {
            c[node] += c[neigh];
        }
    }
}

void calculate_hardness(int node, int par, int outside_distance, int outside_count)
{
    vector<pi> paths;
    if (par != -1 || adj_list[node].size() == 1)
        paths.pb(mp(outside_distance, outside_count));

    for (auto neigh : adj_list[node]) if (neigh != par)
        paths.pb(mp(d[neigh] + 1, c[neigh]));

    sort(paths.begin(), paths.end(), [&] (pi&a, pi& b) {return a > b;});

    if (paths.size() >= 3 && paths[0].f * (paths[1].f + paths[2].f) >= ans.f) {
        // Calculate maximum distance
        // Paths that are available are : c[1] * c[2] (if all dist are distinct)
        ll curdist = paths[0].f * (paths[1].f + paths[2].f);
        ll third_chances = 0;
        ll total_chances = 0;

        for (auto p : paths)
            if (p.f == paths[2].f)
                third_chances += p.s;

        if (paths[1].f == paths[2].f) {
            // Many pairing possibilities
            total_chances = third_chances * third_chances;
            for (auto p : paths)
                if (p.f == paths[2].f) {
                    // Remove the chances going into the same path twice
                    total_chances -= (p.s) * (p.s);
                }

            // We have doublecounted each path(front to back and back to front)
            // It is the same path, therefore half the result
            total_chances /= 2;
        }
        else if (paths[0].f == paths[1].f) {
            // We can use both first and second paths in our chance calculation
            total_chances = third_chances * (paths[0].s + paths[1].s);
        }
        else {
            // All distinct
            total_chances = third_chances * paths[1].s;
        }

        if (ans.f < curdist) {
            ans = mp(curdist, total_chances);
        }
        else {
            ans.s += total_chances;
        }
    }

    // Calculate the best path to give to children
    ll d1 = paths[0].f + 1;
    ll d2 = 0;
    ll c2 = 1;
    ll c1 = 0;
    if (paths.size() >= 2) {
        d2 = paths[1].f + 1;
        c2 = 0;

        for (auto p : paths) {
            if (p.f + 1 == d1)
                c1 += p.s;
            if (p.f + 1 == d2)
                c2 += p.s;
        }
    }

    paths.clear();
    for (auto neigh : adj_list[node]) {
        if (neigh != par) {
            if (d[neigh] + 2 == d1 && c[neigh] == c1)
                calculate_hardness(neigh, node, d2, c2);
            else if (d[neigh] + 2 == d1)
                calculate_hardness(neigh, node, d1, c1 - c[neigh]);
            else
                calculate_hardness(neigh, node, d1, c1);
        }
    }
}

int main(void)
{
    scanf("%d", &N);

    adj_list.resize(N);
    d.resize(N);
    c.resize(N);
    ans = mp(0, 1);

    for (int i = 0; i < N - 1; i++) {
        int a, b;
        scanf("%d %d", &a, &b);
        a--; b--;

        adj_list[a].pb(b);
        adj_list[b].pb(a);
    }

    calc_height(0, -1);
    calculate_hardness(0, -1, 0, 1);

    printf("%lld %lld\n", ans.f, ans.s);

    return 0;
}

Compilation message

road.cpp: In function 'int main()':
road.cpp:119:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  119 |     scanf("%d", &N);
      |     ~~~~~^~~~~~~~~~
road.cpp:128:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |         scanf("%d %d", &a, &b);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 296 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 276 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 300 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 212 KB Output is correct
23 Correct 1 ms 212 KB Output is correct
24 Correct 1 ms 212 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 296 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 276 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 300 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 212 KB Output is correct
23 Correct 1 ms 212 KB Output is correct
24 Correct 1 ms 212 KB Output is correct
25 Correct 2 ms 952 KB Output is correct
26 Correct 2 ms 1108 KB Output is correct
27 Correct 2 ms 1076 KB Output is correct
28 Correct 2 ms 1108 KB Output is correct
29 Correct 3 ms 980 KB Output is correct
30 Correct 2 ms 1108 KB Output is correct
31 Correct 2 ms 1108 KB Output is correct
32 Correct 2 ms 980 KB Output is correct
33 Correct 2 ms 980 KB Output is correct
34 Correct 2 ms 1108 KB Output is correct
35 Correct 2 ms 1108 KB Output is correct
36 Correct 3 ms 1108 KB Output is correct
37 Correct 2 ms 1244 KB Output is correct
38 Correct 3 ms 1508 KB Output is correct
39 Correct 2 ms 980 KB Output is correct
40 Correct 2 ms 828 KB Output is correct
41 Correct 3 ms 692 KB Output is correct
42 Correct 2 ms 696 KB Output is correct
43 Correct 2 ms 596 KB Output is correct
44 Correct 2 ms 596 KB Output is correct
45 Correct 2 ms 596 KB Output is correct
46 Correct 3 ms 568 KB Output is correct
47 Correct 2 ms 724 KB Output is correct
48 Correct 2 ms 852 KB Output is correct

Subtask #3
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 296 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 276 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 300 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 212 KB Output is correct
23 Correct 1 ms 212 KB Output is correct
24 Correct 1 ms 212 KB Output is correct
25 Correct 2 ms 952 KB Output is correct
26 Correct 2 ms 1108 KB Output is correct
27 Correct 2 ms 1076 KB Output is correct
28 Correct 2 ms 1108 KB Output is correct
29 Correct 3 ms 980 KB Output is correct
30 Correct 2 ms 1108 KB Output is correct
31 Correct 2 ms 1108 KB Output is correct
32 Correct 2 ms 980 KB Output is correct
33 Correct 2 ms 980 KB Output is correct
34 Correct 2 ms 1108 KB Output is correct
35 Correct 2 ms 1108 KB Output is correct
36 Correct 3 ms 1108 KB Output is correct
37 Correct 2 ms 1244 KB Output is correct
38 Correct 3 ms 1508 KB Output is correct
39 Correct 2 ms 980 KB Output is correct
40 Correct 2 ms 828 KB Output is correct
41 Correct 3 ms 692 KB Output is correct
42 Correct 2 ms 696 KB Output is correct
43 Correct 2 ms 596 KB Output is correct
44 Correct 2 ms 596 KB Output is correct
45 Correct 2 ms 596 KB Output is correct
46 Correct 3 ms 568 KB Output is correct
47 Correct 2 ms 724 KB Output is correct
48 Correct 2 ms 852 KB Output is correct
49 Correct 443 ms 77688 KB Output is correct
50 Correct 458 ms 84264 KB Output is correct
51 Correct 459 ms 89772 KB Output is correct
52 Correct 440 ms 69904 KB Output is correct
53 Correct 360 ms 87060 KB Output is correct
54 Correct 381 ms 94248 KB Output is correct
55 Correct 357 ms 76620 KB Output is correct
56 Correct 390 ms 84328 KB Output is correct
57 Correct 433 ms 93924 KB Output is correct
58 Correct 398 ms 86476 KB Output is correct
59 Correct 391 ms 86348 KB Output is correct
60 Correct 399 ms 82828 KB Output is correct
61 Correct 665 ms 136072 KB Output is correct
62 Correct 663 ms 119004 KB Output is correct
63 Correct 603 ms 69496 KB Output is correct
64 Correct 617 ms 57680 KB Output is correct
65 Correct 613 ms 50280 KB Output is correct
66 Correct 543 ms 46156 KB Output is correct
67 Correct 554 ms 44088 KB Output is correct
68 Correct 549 ms 43212 KB Output is correct
69 Correct 549 ms 42844 KB Output is correct
70 Correct 618 ms 42584 KB Output is correct
71 Correct 577 ms 42484 KB Output is correct
72 Correct 547 ms 42796 KB Output is correct
73 Correct 580 ms 43052 KB Output is correct
74 Correct 553 ms 43368 KB Output is correct
75 Correct 521 ms 43892 KB Output is correct
76 Correct 493 ms 45136 KB Output is correct
77 Correct 436 ms 47636 KB Output is correct
78 Correct 297 ms 52976 KB Output is correct