oj.uz

Submission #108717

# Submission time Handle Problem Language Result Execution time Memory
108717 2019-05-01T07:11:36 Z oolimry Duathlon (APIO18_duathlon) C++14
0 / 100
 11 ms 8192 KB 
#include <bits/stdc++.h>

using namespace std;
int n, m;
typedef vector<int> vi;
typedef pair<int,int> ii;
struct node{
    int depth = -1;
    int low;
    int parent;
    bool vis = false;
    bool isArti = false;
    vi adj;
};

vector<unordered_set<int> > biconnected;
stack<int> s; ///this is only needed for biconnected components
///note: this will ignore single nodes with no edges
static node g[200005];
int rootChildren = 0;
void dfs(int u){
    if(g[u].depth == -1) g[u].depth = g[g[u].parent].depth + 1;
    g[u].low = g[u].depth;
    g[u].vis = true;
    for(int i = 0;i < g[u].adj.size();i++){
        int v = g[u].adj[i];
        if(!g[v].vis){
            g[v].parent = u;
            if(g[u].depth == 0) rootChildren++;
            s.push(u); ///s traces the path of tree traversal
            dfs(v);
            g[u].low = min(g[u].low,g[v].low);

            if(g[v].low >= g[u].depth){
                g[u].isArti = true;
                g[u].low = min(g[u].low,g[v].low);
                unordered_set<int> newSet;
                int nn;
                biconnected.push_back(newSet); ///create new biconnected component
                do{
                    assert(!s.empty());
                    nn = s.top();
                    s.pop();
                    biconnected.back().insert(nn);
                }while(nn != u);
            }
            ///if(g[v].low > g[u].depth{
                  ///u,v is a bridge
            ///}
        }
        else if(v != g[u].parent){
            g[u].low = min(g[u].low,g[v].low);
        }
        s.push(u);
    }
}
struct node2{
    long long sz;
    long long dp = 0;
    bool isArti = false;
    bool vis = false;
    int r;
    int p = -1;
    vi adj;
};

vector<node2> bct; ///block-cut tree
long long root = -1;
void dp(int u){
    if(bct[u].vis) return;
    bct[u].vis = true;
    bct[u].dp = bct[u].sz;
    bct[u].r = root;
    for(int i = 0;i < bct[u].adj.size();i++){
        int v = bct[u].adj[i];
        if(bct[v].vis) continue;
        bct[v].p = u;
        dp(v);
        bct[u].dp += bct[v].dp;
    }
}
int main()
{
    freopen("i.txt","r",stdin);
    cin >> n >> m;
    ii edges[m];
    for(int i = 0;i < m;i++){
        int a, b;
        cin >> a >> b;
        a--;
        b--;
        g[a].adj.push_back(b);
        g[b].adj.push_back(a);
        edges[i] = ii(a,b);
    }

    for(int i = 0;i < n;i++){
        if(!g[i].vis){
            rootChildren = 0;
            g[i].depth = 0;
            dfs(i);
            if(rootChildren > 1) g[i].isArti = true;
            else g[i].isArti = false; ///this line is needed
        }
    }
    unordered_map<int,int> artis;
    for(int i = 0;i < n;i++){
        if(g[i].isArti){
            artis[i] = bct.size();
            node2 nn;
            nn.sz = 1;
            nn.isArti = true;
            bct.push_back(nn);
        }
    }


    for(int i = 0;i < biconnected.size();i++){
        node2 nn;
        nn.sz = biconnected[i].size();
        nn.isArti = false;
        for(unordered_set<int>::iterator it = biconnected[i].begin();it != biconnected[i].end();it++){
            //cout << *it << " ";
            if(artis.find(*it) != artis.end()){
                nn.adj.push_back(artis[*it]);
                bct[artis[*it]].adj.push_back(bct.size());
                nn.sz--;
            }
        }
        bct.push_back(nn);
        //cout << "\n";
    }
    for(int i = 0;i < bct.size();i++){
        root = i;
        dp(i);
    }
    set<long long> checl;

    for(int i = 0;i < bct.size();i++){
        //cout << i << " " << bct[i].sz << " " << bct[i].dp << " " << bct[i].isArti << "| ";
        for(int j = 0;j < bct[i].adj.size();j++){
            //cout << bct[i].adj[j] << " ";
            long long q = i * 1000000000ll + j;
            if(checl.find(q) != checl.end()) assert(false);
            else checl.insert(q);
        }
        //cout << "\n";
    }

    long long ans = 0ll;
    for(int i = 0;i < bct.size();i++){
        vector<long long> branches;
        vector<long long> branchStart;
        long long total = 0ll;
        for(int j = 0;j < bct[i].adj.size();j++){
            if(bct[i].adj[j] != bct[i].p){
                branches.push_back(bct[bct[i].adj[j]].dp);
                branchStart.push_back(bct[bct[i].adj[j]].sz);
            }
        }
        if(bct[i].p >= 0){
            branches.push_back(bct[bct[i].r].dp - bct[i].dp);
            branchStart.push_back(bct[bct[i].p].sz);
        }
        for(int j = 0;j < branches.size();j++) total += branches[j];
        /*
        long long extra = 0, extra2 = 0;
        if(!bct[i].isArti) extra = max(0ll,(long long)(bct[i].adj.size())-2);
        if(!bct[i].isArti) extra2 = max(0ll,(long long)(bct[i].adj.size())-1);
        for(int j = 0;j < branches.size();j++){
            //cout << i << " " << branches[j] << "\n";
            ///branch1 to self or neighbor articulation point to branch2
            ans += branches[j] * (total - branches[j]) * (bct[i].sz + extra);

            ///branch to self to self or self to self to branch
            ans += 2 * (bct[i].sz) * (bct[i].sz + extra2 - 1) * branches[j];

            ///self to arti to another branch
            //if(!bct[i].isArti){
            //    ans += 2ll * (bct[i].sz) * branches[j] * (bct[i].adj.size() - 1);
            //}

            if(bct[i].isArti){
                ///direct branch to self to same branch(not reverse) or its reverse
                ans += 2ll * bct[i].sz * branchStart[j] * (branches[j] - branchStart[j]);
                ///direct branch to self to direct or its reverse
                ans += bct[i].sz * (branchStart[j]) * (branchStart[j] - 1);

            }
        }


        ///self to self to self
        ans += (bct[i].sz) * (bct[i].sz - 1) * (bct[i].sz - 2);
        */

        long long sz = bct[i].sz;
        if(!bct[i].isArti){
            ans += sz * (sz - 1) * (sz + bct[i].adj.size() - 2);
            ans += 2ll * sz * (sz + bct[i].adj.size() - 2) * total;
        }
        long long others = bct[bct[i].r].dp - bct[i].dp;
        for(int j = 0;j < bct[i].adj.size();j++){
            int v = bct[i].adj[j];
            if(v != bct[i].p){
                long long extra = 0;
                if(!bct[i].isArti) extra = bct[i].adj.size()-2;
                ans += 2ll * (bct[i].sz + extra) * bct[v].dp * others;
                others += bct[v].dp;
            }
        }


        //if(!bct[i].isArti) ans += (bct[i].sz) * (bct[i].sz - 1) * (bct[i].adj.size());
        //cout << i << " " << ans << "\n";
    }
    cout << ans;
}

/*
8 7
8 5
8 1
7 5
8 6
3 1
3 2
8 3
*/
/*
10 12
6 4
10 3
4 2
4 1
4 3
6 5
9 1
9 4
2 1
9 3
8 5
7 2
*/

Compilation message

count_triplets.cpp: In function 'void dfs(int)':
count_triplets.cpp:25:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < g[u].adj.size();i++){
                   ~~^~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'void dp(int)':
count_triplets.cpp:74:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < bct[u].adj.size();i++){
                   ~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int main()':
count_triplets.cpp:118:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < biconnected.size();i++){
                   ~~^~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:133:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < bct.size();i++){
                   ~~^~~~~~~~~~~~
count_triplets.cpp:139:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < bct.size();i++){
                   ~~^~~~~~~~~~~~
count_triplets.cpp:141:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0;j < bct[i].adj.size();j++){
                       ~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp:151:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0;i < bct.size();i++){
                   ~~^~~~~~~~~~~~
count_triplets.cpp:155:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0;j < bct[i].adj.size();j++){
                       ~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp:165:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0;j < branches.size();j++) total += branches[j];
                       ~~^~~~~~~~~~~~~~~~~
count_triplets.cpp:203:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j = 0;j < bct[i].adj.size();j++){
                       ~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp:84:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("i.txt","r",stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 8192 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 8192 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 8.0

# Verdict Execution time Memory Grader output
1 Incorrect 11 ms 8088 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 9 ms 8172 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 8064 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 8192 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Incorrect 9 ms 8192 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #8
0 / 8.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 8192 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 8192 KB Output isn't correct
2 Halted 0 ms 0 KB -