Submission #552791

#	Time	Username	Problem	Language	Result	Execution time	Memory
552791		zaneyu	Duathlon (APIO18_duathlon)	C++14	100 / 100	107 ms	29104 KiB

count_triplets

/*input
4 4
1 2 
2 3
3 4
4 2
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
//order_of_key #of elements less than x
// find_by_order kth element
typedef long long int ll;

#define ld long double
#define pii pair<int,int>
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=1e5+10;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
int MOD=2;
const int INF=0x3f3f3f3f;
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
    out<<P.f<<' '<<P.s;
    return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
    REP(i,sz(V)) out<<V[i]<<((i!=sz(V)-1)?" ":"");
    return out;
}
int mult(ll a,ll b){
    if(a<0) a+=MOD;
    return (a*b)%MOD;
}
ll mypow(ll a,ll b){
    if(b<=0) return 1;
    ll res=1LL;
    while(b){
        if(b&1) res=mult(res,a);
        a=mult(a,a);
        b>>=1;
    }
    return res;
}
int low[maxn],dep[maxn];
int cur=0;
vector<int> stk;
int cnt;
bool vis[maxn];
vector<int> v[maxn];
vector<int> g[2*maxn];
int val[2*maxn],sz[2*maxn];
int n;
int num=0;
void dfs(int u){
    low[u]=dep[u]=cur++;
    vis[u]=1;
    val[u]=-1;
    stk.pb(u);
    ++num;
    for(int x:v[u]){
        if(!vis[x]){
            dfs(x);
            MNTO(low[u],low[x]);
            if(low[x]==dep[u]){
                while(sz(stk)){
                    int a=stk.back();
                    g[a].pb(cnt);
                    g[cnt].pb(a);
                    stk.pop_back();
                    if(a==x) break;
                }
                g[u].pb(cnt);
                g[cnt].pb(u);
                val[cnt]=sz(g[cnt]);
                ++cnt;
            }
        }
        else{
            MNTO(low[u],dep[x]);
        }
    }
}
ll ans=0;
void dfs2(int u,int p){
    sz[u]=(u<n);
    for(int x:g[u]){
        if(x==p) continue;
        dfs2(x,u);
        ans+=2LL*val[u]*sz[u]*sz[x];
        sz[u]+=sz[x];
    }
    ans+=2LL*val[u]*sz[u]*(num-sz[u]);
}
int32_t main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int m;
    cin>>n>>m;
    cnt=n;
    REP(i,m){
        int a,b;
        cin>>a>>b;
        --a,--b;
        v[a].pb(b),v[b].pb(a);
    }
    REP(i,n){
        if(!vis[i]){
            num=0;
            dfs(i);
            dfs2(i,-1);
        }
    }
    cout<<ans;
}   

• 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