Submission #60212

#	Time	Username	Problem	Language	Result	Execution time	Memory
60212		duality	Duathlon (APIO18_duathlon)	C++11	100 / 100	319 ms	86224 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
typedef long long int LLI;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pii> vpii;

vi adjList[100000];
int disc[100000],low[100000],art[100000],num = 0;
vi com[100000];
vpii S;
int bcc = 0;
int doDFS(int u,int p) {
    int i,c = 0;
    disc[u] = low[u] = num++;
    for (i = 0; i < adjList[u].size(); i++) {
        int v = adjList[u][i];
        if (disc[v] == -1) {
            c++;
            S.pb(mp(u,v));
            doDFS(v,u);
            low[u] = min(low[u],low[v]);
            if (((p == -1) && (c > 1)) || ((p != -1) && (low[v] >= disc[u]))) {
                art[u] = 1;
                while (1) {
                    int uu = S.back().first,vv = S.back().second;
                    S.pop_back();
                    com[bcc].pb(uu),com[bcc].pb(vv);
                    if ((u == uu) && (v == vv)) break;
                }
                bcc++;
            }
        }
        else if ((v != p) && (disc[v] < disc[u])) low[u] = min(low[u],disc[v]),S.pb(mp(u,v));
    }
    return 0;
}
int size[100000];
vi adjList2[200000];
LLI ans = 0;
int visited[200000],sub[200000];
int doDFS2(int u,int p) {
    int i;
    sub[u] = ((u < bcc) ? size[u]:0);
    visited[u] = 1;
    for (i = 0; i < adjList2[u].size(); i++) {
        int v = adjList2[u][i];
        if (v != p) sub[u] += doDFS2(v,u);
    }
    return sub[u];
}
int doDFS3(int u,int p,int r) {
    int i;
    int c = sub[r]-sub[u];
    if (u < bcc) ans += 2LL*size[u]*size[u]*(sub[r]-size[u]);
    for (i = 0; i < adjList2[u].size(); i++) {
        int v = adjList2[u][i];
        if (v != p) {
            doDFS3(v,u,r);
            if (u < bcc) ans += 2LL*size[u]*sub[v]*c;
            c += sub[v];
        }
    }
    return 0;
}
int main() {
    int i;
    int n,m,u,v;
    scanf("%d %d",&n,&m);
    for (i = 0; i < m; i++) {
        scanf("%d %d",&u,&v);
        u--,v--;
        adjList[u].pb(v);
        adjList[v].pb(u);
    }

    int j;
    for (i = 0; i < n; i++) disc[i] = low[i] = -1;
    for (i = 0; i < n; i++) {
        if (disc[i] == -1) {
            doDFS(i,-1);
            if (!S.empty()) {
                while (!S.empty()) {
                    int u = S.back().first,v = S.back().second;
                    S.pop_back();
                    com[bcc].pb(u),com[bcc].pb(v);
                }
                bcc++;
            }
        }
    }
    for (i = 0; i < bcc; i++) {
        sort(com[i].begin(),com[i].end());
        com[i].resize(unique(com[i].begin(),com[i].end())-com[i].begin());
        for (j = 0; j < com[i].size(); j++) {
            if (art[com[i][j]]) {
                adjList2[i].pb(com[i][j]+bcc);
                adjList2[com[i][j]+bcc].pb(i);
            }
        }
        size[i] = com[i].size()-1;
        ans += (LLI) com[i].size()*(com[i].size()-1)*(com[i].size()-2);
        ans += (LLI) size[i]*size[i];
    }
    for (i = 0; i < bcc; i++) {
        if (!visited[i]) {
            doDFS2(i,-1);
            doDFS3(i,-1,i);
            ans -= (LLI) sub[i]*sub[i];
        }
    }
    printf("%lld\n",ans);

    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int doDFS(int, int)':
count_triplets.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int doDFS2(int, int)':
count_triplets.cpp:48:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList2[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int doDFS3(int, int, int)':
count_triplets.cpp:58:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (i = 0; i < adjList2[u].size(); i++) {
                 ~~^~~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int main()':
count_triplets.cpp:97:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (j = 0; j < com[i].size(); j++) {
                     ~~^~~~~~~~~~~~~~~
count_triplets.cpp:71:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&n,&m);
     ~~~~~^~~~~~~~~~~~~~~
count_triplets.cpp:73:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&u,&v);
         ~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 8 / 8
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 15 / 15
• Subtask 7: 20 / 20
• Subtask 8: 8 / 8
• Subtask 9: 10 / 10