Submission #1074890

#	Time	Username	Problem	Language	Result	Execution time	Memory
1074890		pawned	Naval battle (CEOI24_battle)	C++17	30 / 100	421 ms	32888 KiB

Main

#pragma GCC optimize("O1,O2,O3,Ofast,unroll-loops")

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

#define fi first
#define se second
#define pb push_back
typedef long long ll;
typedef pair<ll, ll> ii;
typedef vector<ll> vi;

const char nl = '\n';

void fastIO() {
	ios::sync_with_stdio(false);
	cin.tie(0);
}

map<char, int> conv = {{'S', 0}, {'N', 1}, {'E', 2}, {'W', 3}};

int main() {
	fastIO();
	int N;
	cin>>N;
	vector<pair<int, ii>> ships;
	// {type, {x, y}}
	map<ll, vector<pair<ii, ii>>> alld;	// all on diagonal x+y=i, going down
	// set of {{x, y}, {type, id}}
	for (int i = 0; i < N; i++) {
		ll x, y; char d;
		cin>>x>>y>>d;
		ships.pb({conv[d], {x, y}});
		alld[x + y].pb({{x, y}, {conv[d], i}});
	}
/*	cout<<"ships: ";
	for (pair<int, ii> p : ships)
		cout<<"("<<p.fi<<", "<<p.se.fi<<", "<<p.se.se<<"); ";
	cout<<endl;*/
	vector<bool> alive(N, true);	// still alive
	for (pair<ll, vector<pair<ii, ii>>> pr : alld) {
//		cout<<"at "<<pr.fi<<endl;
		sort(pr.se.begin(), pr.se.end());
		int K = pr.se.size();
		vector<char> dir;	// A = east, B = south
		vi idx;
		for (int j = 0; j < K; j++) {
			if (pr.se[j].se.fi == 2)
				dir.pb('A');
			else
				dir.pb('B');
			idx.pb(pr.se[j].se.se);
		}
/*		cout<<"K: "<<K<<endl;
		cout<<"dir: ";
		for (char c : dir)
			cout<<c<<" ";
		cout<<endl;
		cout<<"idx: ";
		for (int x : idx)
			cout<<x<<" ";
		cout<<endl;*/
		// remove all consec
		stack<int> q;	// all existing A ids, most recent on top
		for (int j = 0; j < K; j++) {
			if (dir[j] == 'A') {
				q.push(idx[j]);
			}
			else {
				if (!q.empty()) {
					int x = q.top();
					q.pop();
//					cout<<"removed "<<x<<" "<<idx[j]<<endl;
					alive[x] = false;
					alive[idx[j]] = false;
				}
			}
		}
	}
//	cout<<"ANSWER: "<<endl;
	for (int i = 0; i < N; i++) {
		if (alive[i])
			cout<<(i + 1)<<endl;
	}
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 6
• Subtask 2: 0 / 12
• Subtask 3: 0 / 8
• Subtask 4: 0 / 11
• Subtask 5: 0 / 9
• Subtask 6: 30 / 30
• Subtask 7: 0 / 24