Submission #422733

#	Time	Username	Problem	Language	Result	Execution time	Memory
422733		amunduzbaev	Making Friends on Joitter is Fun (JOI20_joitter2)	C++14	100 / 100	1327 ms	79084 KiB

joitter2

/* made by amunduzbaev */
 
//~ #include <ext/pb_ds/assoc_container.hpp>
//~ #include <ext/pb_ds/tree_policy.hpp>
#include "bits/stdc++.h"
 
using namespace std;
//~ using namespace __gnu_pbds;

#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define NeedForSpeed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define vv vector
#define mem(arr, v) memset(arr, v, sizeof arr)
#define int long long
 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii; 
typedef vector<int> vii;
typedef vector<pii> vpii;
template<class T> bool umin(T& a, const T& b) { return a > b ? a = b, true : false; }
template<class T> bool umax(T& a, const T& b) { return a < b ? a = b, true : false; }
template<int sz> using tut = array<int, sz>;
void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);  
	freopen((s+".out").c_str(),"w",stdout); NeedForSpeed }
//~ template<class T> using oset = tree<T, 
//~ null_type, less_equal<T>, rb_tree_tag, 
//~ tree_order_statistics_node_update> ordered_set;
 
const int N = 2e5+5;
const int mod = 1e9+7;
const ll inf = 1e18;
const ld Pi = acos(-1);
 
#define MULTI 0
int n, m, k, s, t, q, ans, res, a[N];
int par[N], sz[N];
set<int> in[N], tocomp[N], fromcomp[N];
queue<pii> qq;

void add(int a, int b){
	tocomp[a].insert(b), fromcomp[b].insert(a);
	if(tocomp[b].count(a) && fromcomp[a].count(b)) qq.push({a, b});
}

int f(int x) { return (x == par[x] ? x : par[x] = f(par[x])); }
void merge(int a, int b){
	a = f(a), b = f(b);
	if(a == b) return;
	if(sz(in[a]) + sz(tocomp[a]) + sz(fromcomp[a]) < sz(in[b]) + sz(tocomp[b]) + sz(fromcomp[b])) swap(a, b);
	res += (sz(in[a]) * sz[b] + sz(in[b]) * sz[a]);
	par[b] = a, sz[a] += sz[b];
	for(auto x : in[b]){
		if(in[a].count(x)) res -= sz[a];
		else in[a].insert(x);
	}
	
	tocomp[a].erase(b), fromcomp[a].erase(b);
	tocomp[b].erase(a), fromcomp[b].erase(a);
	for(auto x : tocomp[b]){
		fromcomp[x].erase(b);
		add(a, f(x));
	}
	for(auto x : fromcomp[b]){
		tocomp[x].erase(b);
		add(f(x), a);
	}
	
	tocomp[b].clear(), fromcomp[b].clear(), in[b].clear();
}

void solve(int t_case){
	cin>>n>>m;
	for(int i=1;i<=n;i++) in[i].insert(i), par[i] = i, sz[i] = 1;
	while(m--){
		int a, b; cin>>a>>b;
		if(f(a) == f(b) || in[f(b)].count(a)){
			cout<<res<<"\n";
			continue;
		} in[f(b)].insert(a);
		res += sz[f(b)];
		add(f(a), f(b));
		
		while(!qq.empty()){
			int a = qq.front().ff, b = qq.front().ss; qq.pop();
			merge(a, b);
		} cout<<res<<"\n";
	}
}

signed main(){
	NeedForSpeed
	if(MULTI){
		int t; cin>>t;
		for(int t_case = 1; t_case <= t; t_case++) solve(t_case);
	} else solve(1);
	return 0;
}

Compilation message (stderr)

joitter2.cpp: In function 'void usaco(std::string)':
joitter2.cpp:32:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 | void usaco(string s) { freopen((s+".in").c_str(),"r",stdin);
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
joitter2.cpp:33:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |  freopen((s+".out").c_str(),"w",stdout); NeedForSpeed }
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 16 / 16
• Subtask 3: 83 / 83