Submission #1027958

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027958		Issa	Tiles (BOI24_tiles)	C++17	30 / 100	31 ms	11612 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"

const int maxn = 1e6 + 100;
const ll INF = (ll)1e18 + 100;
const int inf = 1e9 + 100;
const int MOD = 1e9 + 123;
const int maxl = 26;
const int P = 31;

int n, m;
int a[maxn];
int b[maxn];
int c[1010][1010];
vector<int> s;
struct asd{
	int r, cr;
	int l, cl;
	int ok[2];
} d[maxn * 4];
int t[maxn * 4];

void calc(int v, int tl, int tr, int mid){
	d[v].ok[0] = d[v<<1].ok[0] & d[v<<1|1].ok[0];
	d[v].ok[1] = d[v<<1].ok[1] & d[v<<1|1].ok[1];
	if(d[v<<1].l > s[tl] && d[v<<1|1].r < s[tr]){
		if(d[v<<1].cl == d[v<<1|1].cr){
			d[v].ok[d[v<<1].cl] &= (d[v<<1].l ^ d[v<<1|1].r) & 1;
		} else{
			d[v].ok[d[v<<1].cl] &= (d[v<<1].l ^ s[mid]) & 1;
			d[v].ok[d[v<<1|1].cr] &= (d[v<<1|1].r ^ s[mid+1]) & 1;
		}
	}
	d[v].r = d[v<<1].r;
	d[v].cr = d[v<<1].cr;
	if(d[v<<1|1].cr == d[v].cr && d[v].r == s[mid]) d[v].r = d[v<<1|1].r;
	d[v].l = d[v<<1|1].l;
	d[v].cl = d[v<<1|1].cl;
	if(d[v<<1].cl == d[v].cl && d[v].l == s[mid+1]) d[v].l = d[v<<1].l;
}

void build(int v = 1, int tl = 0, int tr = s.size() - 1){
	if(tl == tr){
		d[v] = {s[tl], 0, s[tl], 0, {1, 1}};
	} else{
		int mid = (tl + tr) >> 1;
		build(v<<1, tl, mid);
		build(v<<1|1, mid+1, tr);
		calc(v, tl, tr, mid);
	}
}

void pre(int v){
	t[v] ^= 1;
	d[v].cr ^= 1;
	d[v].cl ^= 1;
	swap(d[v].ok[0], d[v].ok[1]);
}

void push(int v, int tl, int tr){
	if(tl == tr || !t[v]) return;
	t[v] = 0; pre(v<<1); pre(v<<1|1);
}

void upd(int l, int r, int v = 1, int tl = 0, int tr = s.size()-1){
	push(v, tl, tr);
	if(s[tl] > r || s[tr] < l) return;
	if(l <= s[tl] && s[tr] <= r) pre(v);
	else{
		int mid = (tl + tr) >> 1;
		upd(l, r, v<<1, tl, mid);
		upd(l, r, v<<1|1 ,mid+1, tr);
		calc(v, tl, tr, mid);
	}
}

void out(int v = 1, int tl = 0, int tr = s.size() - 1){
	push(v, tl, tr);
	if(tl == tr) cout << d[v].cl << ' ';
	else{
		int mid = (tl + tr) >> 1;
		out(v<<1, tl, mid);
		out(v<<1|1, mid+1, tr);
	}
}

void test(){
	cin >> n >> m;
	int mx = 0;
	bool ok = 1;
	for(int i = 1; i <= n; i++){
		cin >> a[i] >> b[i];
		mx = max(mx, b[i]);
		ok &= (a[i] & 1);
	}
	if(ok){
		vector<pair<int, pii>> g;
		for(int i = 1; i <= n; i++){
			int j = i - 1;
			if(!j) j = n;
			if(a[i] == a[j]){
				int l = min(b[i], b[j]);
				int r = b[i] + b[j] - l;
				r--;
				s.push_back(l);
				s.push_back(r);
				s.push_back(r+1);
				s.push_back(l-1);
				g.push_back({a[i], {l, r}});
			}
		}
		sort(s.begin(), s.end());
		s.resize(unique(s.begin(), s.end()) - s.begin());
		build(); int ans = 0;
		sort(g.begin(), g.end());
		for(int i = 0; i < g.size(); i++){
			auto [l, r] = g[i].second;
			upd(l, r);
			// cout << l << ' ' << r << endl;
			if(i + 1 < g.size() && g[i].first < g[i+1].first){
				// out(); cout << endl;
				int f = d[1].ok[1];
				if(d[1].cr) f &= (d[1].r ^ s[0]) & 1;
				if(d[1].cl) f &= (d[1].l ^ s.back()) & 1;
				if(f){
					ans = g[i+1].first;
				} else break;
			}
		}
		cout << ans;
	} else if(m > 1000 || mx > 1000){
		vector<int> v;
		for(int i = 2; i <= n; i++){
			while(v.size() > 1){
				int k = v[v.size()-2], j = v.back();
				if(a[k] == a[j] && a[j] == a[i]) v.pop_back();
				else if(b[k] == b[j] && b[j] == b[i]) v.pop_back();
				else break;
			} v.push_back(i);
		}
		int ans = 0;
		for(int i: v){
			if((b[i] & 1 )|| !b[i]) break;
			ans = a[i] - (a[i] & 1);
			if(a[i] & 1) break;
		}
		cout << ans;
	} else{
		for(int i = 1; i <= n; i++){
			int j = i - 1;
			if(!j) j = n;
			if(a[i] == a[j]){
				int l = min(b[i], b[j]);
				int r = b[i] + b[j] - l;
				for(int y = l; y < r; y++){
					c[a[i]][y] ^= 1;
				}
			}
		}
		for(int i = 0; i < m; i++){
			for(int j = 0; j <= 1000; j++){
				if(i) c[i][j] ^= c[i-1][j];
			}
		}
		int ans = 0;
		for(int i = 0; i < m; i++){
			int ok = 0;
			for(int j = 0; j <= 1000; j++){
				if(c[i][j]){
					ok = 1;
					if(c[i+1][j] && c[i][j+1] && c[i+1][j+1]){
						c[i][j] = 0;
						c[i+1][j] = 0;
						c[i][j+1] = 0;
						c[i+1][j+1] = 0;
					} else{
						ok = 2;
						break;
					}
				}
			}
			if(ok == 2) break;
			if(ok == 1) continue;
			ans = i + 1;
		}
		cout << ans;
	}
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; t = 1;
    while(t--) test();
    cout << ent;
}

Compilation message (stderr)

Main.cpp: In function 'void test()':
Main.cpp:120:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |   for(int i = 0; i < g.size(); i++){
      |                  ~~^~~~~~~~~~
Main.cpp:124:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  124 |    if(i + 1 < g.size() && g[i].first < g[i+1].first){
      |       ~~~~~~^~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 9
• Subtask 3: 11 / 11
• Subtask 4: 19 / 19
• Subtask 5: 0 / 22
• Subtask 6: 0 / 25
• Subtask 7: 0 / 10