Submission #456330

#	Time	Username	Problem	Language	Result	Execution time	Memory
456330		dutch	Flood (IOI07_flood)	C++17	33 / 100	193 ms	27256 KiB

flood

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5+1, M = N+N;

int n, m, x[N], y[N], a[M], b[M], up[N], dn[N], lf[N], rt[N], d[M*2];
bool vertical[M], vis[M*2];
vector<int> g[M*2], ans;

signed main(){
	cin.tie(0)->sync_with_stdio(0);
	cin >> n;
	for(int i=1; i<=n; ++i)
		cin >> x[i] >> y[i];
	cin >> m;
	for(int i=1; i<=m; ++i){
		int &u = a[i], &v = b[i];
		cin >> u >> v;
		if((vertical[i] = (x[u] == x[v]))){
			if(y[u] > y[v]) swap(u, v);
			up[u] = dn[v] = i;
		}else{
			if(x[u] > x[v]) swap(u, v);
			rt[u] = lf[v] = i;
		}
	}
	vis[0] = 1;
	for(int i=1; i<=m+m; ++i){
		int u = i, v;
		while(!vis[u]){
			vis[u] = !(v = 0);
			int w = u;
			if(vertical[((u-1) % m) + 1]){
				if(u > m){ // right
					u -= m;
					if(rt[a[u]] && !v) v = rt[a[u]] + m;
					if(dn[a[u]] && !v) v = dn[a[u]] + m;
					if(lf[a[u]] && !v) v = lf[a[u]];
					if(up[a[u]] && !v) v = up[a[u]];
				}else{
					if(lf[b[u]] && !v) v = lf[b[u]];
					if(up[b[u]] && !v) v = up[b[u]];
					if(rt[b[u]] && !v) v = rt[b[u]] + m;
					if(dn[b[u]] && !v) v = dn[b[u]] + m;
				}
			}else{
				if(u > m){ // up
					u -= m;
					if(up[b[u]] && !v) v = up[b[u]];
					if(rt[b[u]] && !v) v = rt[b[u]] + m;
					if(dn[b[u]] && !v) v = dn[b[u]] + m;
					if(lf[b[u]] && !v) v = lf[b[u]];
				}else{
					if(dn[a[u]] && !v) v = dn[a[u]] + m;
					if(lf[a[u]] && !v) v = lf[a[u]];
					if(up[a[u]] && !v) v = up[a[u]];
					if(rt[a[u]] && !v) v = rt[a[u]] + m;
				}
			}
			if(v){
				g[w].push_back(v);
				g[v].push_back(w);
			}
			u = v;
		}
	}
	deque<int> q;
	int lowest = 0, leftmost = 0;
	for(int i=1; i<=m; ++i){
		if(vertical[i]){
			if(!leftmost || x[a[i]] < x[a[leftmost]]) leftmost = i;
		}else{
			if(!lowest || y[a[i]] < y[a[lowest]]) lowest = i;
		}
	}
	lowest = lowest ? : leftmost;
	q.push_back(lowest);
	fill(d, d+m+m+1, 2e9);
	d[lowest] = 0;
	function<int(int)> f = [&](int z){ return z > m ? z - m : z; };
	while(!q.empty()){
		int u = q.front(); q.pop_front();
		for(int v : g[u]) if(d[v] > d[u]){
			d[v] = d[u];
			q.push_front(v);
		}
		int v = u > m ? u-m : u+m;
		if(d[v] > d[u] + 1){
			d[v] = d[u] + 1;
			q.push_back(v); 
		}
		if(d[u] == d[v]) ans.push_back(min(u, v));
	}
	sort(begin(ans), end(ans));
	ans.resize(unique(begin(ans), end(ans)) - begin(ans));
	cout << size(ans) << '\n';
	for(int i : ans) cout << i << '\n';
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 0 / 3
• Subtask 5: 0 / 10
• Subtask 6: 3 / 3
• Subtask 7: 0 / 3
• Subtask 8: 0 / 3
• Subtask 9: 0 / 3
• Subtask 10: 0 / 9
• Subtask 11: 0 / 9
• Subtask 12: 0 / 9
• Subtask 13: 0 / 9
• Subtask 14: 0 / 9