Submission #209017

#	Time	Username	Problem	Language	Result	Execution time	Memory
209017		jtnydv25	Bridges (APIO19_bridges)	C++14	44 / 100	3078 ms	8196 KiB

bridges

#include <bits/stdc++.h>
using namespace std;
	
#define ll long long
#define sd(x) scanf("%d", &(x))
#define pii pair<int, int>
#define F first
#define S second
#define all(c) ((c).begin()), ((c).end())
#define sz(x) ((int)(x).size())
#define ld long double
	
template<class T,class U>
ostream& operator<<(ostream& os,const pair<T,U>& p){
	os<<"("<<p.first<<", "<<p.second<<")";
	return os;
}
	
template<class T>
ostream& operator <<(ostream& os,const vector<T>& v){
	os<<"{";
	for(int i = 0;i < (int)v.size(); i++){
		if(i)os<<", ";
		os<<v[i];
	}
	os<<"}";
	return os;
}
	
#ifdef LOCAL
#define cerr cout
#else
#endif
	
#define TRACE
	
#ifdef TRACE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1){
	cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args){
	const char* comma = strchr(names + 1, ',');cerr.write(names, comma - names) << " : " << arg1<<" | ";__f(comma+1, args...);
}
#else
#define trace(...)
#endif
	
template<class T>
struct rollback_array{
	struct ct{
		int where; 
		T what;
	};
	stack<ct> changes;
	vector<T> arr;
	int n;
	rollback_array(){n = 0;}
	rollback_array(int n) : n(n), arr(n){};
	void setall(T x){
		for(int i = 0; i < n; i++) arr[i] = x;
	}
	// if not to be rolled back just do arr[x] = v
	int & operator [] (int x){ return arr[x];}
	inline void update(int i, T v){
		changes.push({i, arr[i]});
		arr[i] = v;
	}
	inline void click(){
		changes.push({-1, T()});
	}
	inline void roll_back(){
		while(!changes.empty()){
			auto it = changes.top();
			changes.pop();
			if(it.where == -1) return;
			arr[it.where] = it.what;
		}
	}
};
	
struct rollback_dsu{
	int n;
	rollback_array<int> par, num;
	rollback_dsu(int n) : n(n), par(n), num(n){
		par.setall(-1);
		num.setall(1);
	}
	int root(int x){
		if(par[x] == -1) return x;
		int rt = root(par[x]);
		par.update(x, rt);
		return rt;
	}
	void merge(int x, int y){
		x = root(x);
		y = root(y);
		if(x == y) return;
		if(num[x] > num[y]) swap(x, y);
		par.update(x, y);
		num.update(y, num[x] + num[y]);
	}
	void click(){
		par.click();
		num.click();
	}
	void roll_back(){
		par.roll_back();
		num.roll_back();
	}
};
	
const int N = 100005;
int a[N], b[N], w[2 * N];
int type[N], s[N];
bool changing[N];
const int BLOCK = 505;
int ans[N];
int temp[2 * N];
int cntr = 0;

void go(vector<int> & a, vector<int> & b){
	int pos_a = sz(a) - 1, pos_b = sz(b) - 1;
	cntr = 0;
	while(pos_a >= 0 || pos_b >= 0){
		if(pos_a >= 0 && (pos_b == -1 || w[a[pos_a]] >= w[b[pos_b]])){
			temp[cntr++] = a[pos_a--];
		}
		else{
			temp[cntr++] = b[pos_b--]; 
		}
	}
	for(int i = 1; i < cntr; i++) assert(w[temp[i]] <= w[temp[i - 1]]);
}

int main(){
	int n = 50000, m = 100000; 
	sd(n); sd(m);
	rollback_array<int> W(m);
	for(int i = 0; i < m; i++){
		sd(a[i]); sd(b[i]); sd(w[i]);
		a[i]--; b[i]--;
		W[i] = w[i];
	}
	int q = 100000; 
	sd(q);
	for(int i = 0; i < q; i++){
		sd(type[i]); sd(s[i]); sd(w[i + m]);
		s[i]--;
	}
	vector<int> perm(m); iota(all(perm), 0);
	sort(all(perm), [&](int i, int j){return w[i] < w[j];});
	rollback_dsu D(n);

	for(int i = 0; i * BLOCK < q; i++){
		int st = i * BLOCK, en = min(q - 1, st + BLOCK - 1);
		vector<int> queries;
		memset(changing, 0, sizeof changing);
		vector<int> changing_edges;
		for(int j = st; j <= en; j++){
			if(type[j] == 1){
				changing[s[j]] = 1;
			} else{
				queries.push_back(j + m);
			}
		}
		vector<int> v;
		for(int j = 0; j < m; j++){
			int ind = perm[j];
			if(changing[ind]){
				changing_edges.push_back(ind);
			} else{
				v.push_back(ind);
			}
		}
		sort(all(queries), [&](int p, int q){return w[p] < w[q];});
		
		go(v, queries);
		D.click();
		for(int j = 0; j < cntr; j++){
			if(j) assert(w[temp[j]] <= w[temp[j - 1]]);
			int ind = temp[j];
			if(ind < m){
				if(!changing[ind]){
					D.merge(a[ind], b[ind]);
				}
			} else{
				ind -= m;
				D.click();
				W.click();
				for(int j = st; j < ind; j++){
					if(type[j] == 1) W.update(s[j], w[j + m]);
				}
				for(int e : changing_edges) if(W[e] >= w[ind + m]){
					D.merge(a[e], b[e]);
				}
				ans[ind] = D.num[D.root(s[ind])];
				D.roll_back();
				W.roll_back();
			}
		}
		D.roll_back();
		for(int j = st; j <= en; j++) if(type[j] == 1){
			w[s[j]] = w[j + m];
			W[s[j]] = w[j + m];
		}
		sort(all(changing_edges), [&](int p, int q){return w[p] < w[q];});
		go(v, changing_edges);
		for(int j = 0; j < m; j++) perm[j] = temp[m - 1 - j];
	}

	for(int i = 0; i < q; i++) if(type[i] == 2) printf("%d\n", ans[i]);
}

Compilation message (stderr)

bridges.cpp: In instantiation of 'rollback_array<T>::rollback_array(int) [with T = int]':
bridges.cpp:87:43:   required from here
bridges.cpp:59:6: warning: 'rollback_array<int>::n' will be initialized after [-Wreorder]
  int n;
      ^
bridges.cpp:58:12: warning:   'std::vector<int> rollback_array<int>::arr' [-Wreorder]
  vector<T> arr;
            ^~~
bridges.cpp:61:2: warning:   when initialized here [-Wreorder]
  rollback_array(int n) : n(n), arr(n){};
  ^~~~~~~~~~~~~~
bridges.cpp: In function 'int main()':
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:140:2: note: in expansion of macro 'sd'
  sd(n); sd(m);
  ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:140:9: note: in expansion of macro 'sd'
  sd(n); sd(m);
         ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:143:3: note: in expansion of macro 'sd'
   sd(a[i]); sd(b[i]); sd(w[i]);
   ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:143:13: note: in expansion of macro 'sd'
   sd(a[i]); sd(b[i]); sd(w[i]);
             ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:143:23: note: in expansion of macro 'sd'
   sd(a[i]); sd(b[i]); sd(w[i]);
                       ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:148:2: note: in expansion of macro 'sd'
  sd(q);
  ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:150:3: note: in expansion of macro 'sd'
   sd(type[i]); sd(s[i]); sd(w[i + m]);
   ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:150:16: note: in expansion of macro 'sd'
   sd(type[i]); sd(s[i]); sd(w[i + m]);
                ^~
bridges.cpp:5:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 #define sd(x) scanf("%d", &(x))
               ~~~~~^~~~~~~~~~~~
bridges.cpp:150:26: note: in expansion of macro 'sd'
   sd(type[i]); sd(s[i]); sd(w[i + m]);
                          ^~

• Subtask 1: 13 / 13
• Subtask 2: 0 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 0 / 13
• Subtask 6: 0 / 27