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Submission #13585

# Submission time Handle Problem Language Result Execution time Memory
13585 2015-02-25T00:29:57 Z gs14004 Shymbulak (IZhO14_shymbulak) C++14
95.83 / 100
 1500 ms 27512 KB 
#include <cstdio>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
typedef long long lint;
typedef pair<int,lint> pi;

int n;

vector<int> graph[200005];
int deg[200005];

int piv;
int cycle_num[200005];
int get_cycle[200005];
int vis[200005];
pi cycle_ret[200005];

long long freq[200005];

void label_graph(){
    queue<int> q;
    for (int i=1; i<=n; i++) {
        if(deg[i] == 1){
            q.push(i);
        }
    }
    while (!q.empty()) {
        int x = q.front();
        q.pop();
        deg[x] = 0;
        for (int &i : graph[x]){
            if(deg[i]){
                deg[i]--;
                if(deg[i] == 1){
                    q.push(i);
                }
            }
        }
    }
    for (int i=1; i<=n; i++) {
        if(deg[i]){
            q.push(i);
            break;
        }
    }
    while (!q.empty()) {
        int x = q.front();
        q.pop();
        cycle_num[x] = ++piv;
        get_cycle[cycle_num[x]] = x;
        for (int &i : graph[x]){
            if(deg[i] && !cycle_num[i]){
                q.push(i);
                break;
            }
        }
    }
    for (int i=1; i<=n; i++) {
        if(cycle_num[i]){
            q.push(i);
            vis[i] = 1;
            while (!q.empty()) {
                int x = q.front();
                q.pop();
                for (int &i : graph[x]){
                    if(!vis[i]){
                        vis[i] = 1;
                        q.push(i);
                    }
                }
            }
        }
    }
}

bool cmp(pi a, pi b){
    return a.first > b.first;
}

pi f(int x, int pa){
    vector<pi> sub;
    for (int &i : graph[x]){
        if(i == pa) continue;
        if(cycle_num[i]) continue;
        pi t = f(i,x);
        t.first++;
        sub.push_back(t);
    }
    sort(sub.begin(),sub.end(),cmp);
    if(sub.size() == 0) return pi(0,1);
    if(sub.size() == 1){
        freq[sub[0].first] += sub[0].second;
        return sub[0];
    }
    if(sub[0].first == sub[1].first){
        pi t(sub[0].first,0);
        for (int i=0; i<sub.size(); i++) {
            if(sub[0].first == sub[i].first) t.second += sub[i].second;
        }
        long long sum = 1ll * t.second * t.second;
        for (int i=0; i<sub.size(); i++) {
            if(sub[0].first == sub[i].first) sum -= 1ll * sub[i].second * sub[i].second;
        }
        sum /= 2;
        freq[t.first * 2] += sum;
        return t;
    }
    int low_sub = 0;
    for (int i=1; i<sub.size(); i++) {
        if(sub[1].first == sub[i].first) low_sub += sub[i].second;
    }
    freq[sub[0].first + sub[1].first] += 1ll * low_sub * sub[0].second;
    return sub[0];
}

int main(){
    scanf("%d",&n);
    for (int i=0; i<n; i++) {
        int s,e;
        scanf("%d %d",&s,&e);
        graph[s].push_back(e);
        graph[e].push_back(s);
        deg[s]++;
        deg[e]++;
    }
    label_graph();
    for (int i=1; i<=n; i++) {
        if(cycle_num[i]){
            pi t = f(i,0);
            cycle_ret[cycle_num[i]] = t;
            freq[t.first] += t.second;
        }
    }
    for (int i=1; i<=piv; i++) {
        for (int j=i+1; j<=piv; j++) {
            if(j <= i + piv/2){
                int lng = cycle_ret[i].first + cycle_ret[j].first + j - i;
                freq[lng] += cycle_ret[i].second * cycle_ret[j].second;
            }
            if(j >= i + (piv + 1)/2){
                int lng = cycle_ret[i].first + cycle_ret[j].first + piv - j + i;
                freq[lng] += cycle_ret[i].second * cycle_ret[j].second;
            }
        }
    }
    for (int i=n; i; i--) {
        if(freq[i]){
            printf("%lld",freq[i]);
            return 0;
        }
    }
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 14084 KB Output is correct
2 Correct 0 ms 14084 KB Output is correct
3 Correct 0 ms 14084 KB Output is correct
4 Correct 0 ms 14084 KB Output is correct
5 Correct 3 ms 14084 KB Output is correct
6 Correct 0 ms 14084 KB Output is correct
7 Correct 0 ms 14084 KB Output is correct
8 Correct 0 ms 14084 KB Output is correct
9 Correct 3 ms 14084 KB Output is correct
10 Correct 0 ms 14084 KB Output is correct
11 Correct 0 ms 14084 KB Output is correct
12 Correct 0 ms 14084 KB Output is correct
13 Correct 3 ms 14084 KB Output is correct
14 Correct 0 ms 14084 KB Output is correct
15 Correct 3 ms 14084 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 14084 KB Output is correct
2 Correct 4 ms 14084 KB Output is correct
3 Correct 4 ms 14084 KB Output is correct
4 Correct 0 ms 14084 KB Output is correct
5 Correct 0 ms 14216 KB Output is correct
6 Correct 6 ms 14396 KB Output is correct
7 Correct 0 ms 14216 KB Output is correct
8 Correct 0 ms 14216 KB Output is correct
9 Correct 3 ms 14216 KB Output is correct
10 Correct 4 ms 14216 KB Output is correct

Subtask #3
45.833 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 17248 KB Output is correct
2 Correct 68 ms 17644 KB Output is correct
3 Execution timed out 1500 ms 17248 KB Program timed out
4 Correct 60 ms 17380 KB Output is correct
5 Correct 63 ms 17512 KB Output is correct
6 Correct 162 ms 20020 KB Output is correct
7 Correct 130 ms 19164 KB Output is correct
8 Correct 123 ms 20812 KB Output is correct
9 Correct 127 ms 20812 KB Output is correct
10 Correct 153 ms 21208 KB Output is correct
11 Correct 120 ms 27200 KB Output is correct
12 Correct 134 ms 27512 KB Output is correct