Submission #500073

#	Time	Username	Problem	Language	Result	Execution time	Memory
500073		kaxzert	Duathlon (APIO18_duathlon)	C++17	0 / 100	113 ms	44140 KiB

count_triplets

/**
      ⚡⚡  ⚡⚡      ⚡⚡⚡     ⚡⚡  ⚡⚡  ⚡⚡⚡⚡⚡⚡   ⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡⚡
      ⚡⚡ ⚡⚡      ⚡⚡⚡⚡     ⚡⚡⚡⚡      ⚡⚡      ⚡⚡       ⚡⚡    ⚡⚡  ⚡⚡⚡⚡⚡⚡
      ⚡⚡⚡⚡      ⚡⚡  ⚡⚡      ⚡⚡      ⚡⚡       ⚡⚡⚡⚡⚡   ⚡⚡⚡⚡⚡⚡     ⚡⚡
      ⚡⚡ ⚡⚡    ⚡⚡⚡⚡⚡⚡     ⚡⚡     ⚡⚡         ⚡⚡       ⚡⚡  ⚡⚡       ⚡⚡
      ⚡⚡  ⚡⚡  ⚡⚡     ⚡⚡  ⚡⚡ ⚡⚡  ⚡⚡⚡⚡⚡⚡  ⚡⚡⚡⚡⚡    ⚡⚡   ⚡⚡     ⚡⚡
**/

#include<bits/stdc++.h>

using namespace std;

#define fto(i, a, b) for(int i = a; i <= b; ++i)
#define fdto(i, a, b) for(int i = a; i >= b; --i)
#define bugarr(a, i, j) cout << #a << "{" << i << "..." << j << "}:"; fto(k, i, j-1) cout << a[k] << ", "; cout << a[j] << endl;
#define ll long long
#define db double
#define ldb long double
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define vt vector
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define trav(i, a) for(auto &i : a)
#define sz(a) (int)a.size()
#define pi(a, b) pair<a, b>
#define fast ios::sync_with_stdio(false); cin.tie(0)

string to_bit(int n) {
    string res = "";
    while(n > 0) {
        res += to_string(n&1);
        n >>= 1;
    }
    return res;
}


void setIO(string s) {
    if (sz(s) != 0) {
        freopen((s+".inp").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

void setIOusaco(string s) {
    if (sz(s) != 0) {
        freopen((s+".in").c_str(),"r",stdin);
        freopen((s+".out").c_str(),"w",stdout);
    }
}

template<typename T, typename V>
bool ckmin(T &a, V b) {return (b < a)? a = b, true : false;}
template<typename T, typename V>
bool ckmax(T &a, V b) {return (b > a)? a = b, true : false;}

void print(int x) {cout << x;}
void print(long long x) {cout << x;}
void print(unsigned x) {cout << x;}
void print(unsigned long long x) {cout << x;}
void print(double x) {cout << fixed << x;}
void print(long double x) {cout << fixed << x;}
void print(char x) {cout << "'" << x << "'";}
void print(string x) {cout << '"' << x << '"';}
void print(bool x) {cout << (x ? "true" : "false");}

template<typename T, typename V>
void print(const pair<T, V> &x) {cout << '{'; print(x.ff); cout << ", "; print(x.ss); cout << '}';}
template<typename T>
void print(const T &x) {int f = 0; cout << '{'; for (auto &i: x) cout << (f++ ? ", " : ""), print(i); cout << "}";}
void _print() {cout << "]" << endl;}
template <typename T, typename... V>
void _print(T t, V... v) {print(t); if (sizeof...(v)) cout << ", "; _print(v...);}

#ifdef TAP
#define bug(x...) cout << "[" << #x << "] = ["; _print(x)
#else
#define bug(x...) 
#endif

const int maxN = 100008;

int low[maxN], num[maxN], cnt, color[maxN], articulation[maxN], root, child, n, m, dd[maxN];
vt<int> ke[maxN], block_ke[maxN*4];
ll cnt_color[maxN*4], ans;
vt<vt<pi(int, int)> > bvccs;
stack<pi(int, int)> s;

void dfs(int u, int p = 0) {
	num[u] = low[u] = ++cnt;
	trav(v, ke[u]) {
		if (v == p) continue;
		if (num[v] == 0) {
			s.push({u, v});
			if (u == root) ++child;
			dfs(v, u);
			if (low[v] >= num[u]) {
				articulation[u] = 1;
				vt<pi(int, int)> bvcc;
				while(s.top().ff != u || s.top().ss != v) {
					bvcc.pb(s.top());
					s.pop();
				}
				bvcc.pb(s.top());
				s.pop();
				bvccs.pb(bvcc);
			}
			ckmin(low[u], low[v]);
		} else {
			if (num[u] > num[v]) s.push({u, v});
			ckmin(low[u], num[v]);
		}
	}
}

ll dfs2(int u, int p = 0, int is_cut = 1) {
	num[u] = 1;
	ll res = (is_cut ? 1 : cnt_color[u]);
	ll cntsth = 0;
	vt<ll> f;
	trav(v, block_ke[u]) {
		if (v == p) continue;
		f.pb(dfs2(v, u, is_cut^1));
		if (is_cut == 0) ++cntsth;
	}
	if (is_cut == 0 && p != 0) ++cntsth;
	
	ll sth = accumulate(all(f), 0LL);
	f.pb(n-sth-res);
	ll sum = sth + (n-sth-res);
		bug(u, f, is_cut);
	trav(x, f) {
		ans += x*(sum-x)*res;
		bug(sum, sum-x);
		bug(ans);
	}
	if (is_cut^1) {
		if (cnt_color[u] >= 3) {
			ans += (cnt_color[u])*(cnt_color[u]-1)*(cnt_color[u]-2)*6LL;
		}
		if (cnt_color[u] >= 2) {
			trav(x, f) {
				ans += (cnt_color[u])*(cnt_color[u]-1)/2*x*4LL;
			}
		}
		if (cnt_color[u]+cntsth >= 3) {
			ans += (cnt_color[u]+cntsth-1)*(cnt_color[u]+cntsth-2)*cntsth;
		}
	}
	bug(u);
	bug(ans);

	return sth+res;
}

int main() {
    #ifndef TAP 
    setIO("");
    //setIOusaco("duatholon2018");
    #endif

    fast;

    cin >> n >> m;
    fto(i, 1, m) {
    	int u, v;
    	cin >> u >> v;
    	ke[u].pb(v);
    	ke[v].pb(u);
    }

    fto(i, 1, n) {
    	if (num[i] == 0) {
    		root = i;
    		child = 0;
    		dfs(i, 0);
    		articulation[i] = (child > 1);
    	}
    }

    int dem = 0;
    fto(i, 1, n) {
    	if (articulation[i]) {
    		color[i] = ++dem;
    	}
    }

    auto add = [&](int u) -> void {
    	if (articulation[u]) {
    		if (dd[u] != dem) {
    			block_ke[dem].pb(color[u]);
    			block_ke[color[u]].pb(dem);
    			dd[u] = dem;
    		}
    	} else {
    		cnt_color[dem] += dd[u]^1;
    		dd[u] |= 1;
    		color[u] = dem;
    	}
    };

    vt<int> dd(n+1, 0);
    trav(bvcc, bvccs) {
    	++dem;
    	trav(canh, bvcc) {
    		add(canh.ff);
    		add(canh.ss);
    	}
    }

    fto(i, 1, dem) {
    	num[i] = 0;
    }

    fto(i, 1, dem) {
    	if (num[i] == 0) {
    		dfs2(i);
    	}
    }

    cout << ans << '\n';

    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void setIO(std::string)':
count_triplets.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen((s+".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'void setIOusaco(std::string)':
count_triplets.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |         freopen((s+".in").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         freopen((s+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 0 / 10
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