Submission #66495

#	Time	Username	Problem	Language	Result	Execution time	Memory
66495		kingpig9	Collapse (JOI18_collapse)	C++11	30 / 100	3034 ms	38068 KiB

collapse

#include <bits/stdc++.h>
#include "collapse.h"

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 1e5 + 160;
const int SQRT = 320;

//#define debug(...) fprintf(stderr, __VA_ARGS__)
#define debug(...)
#define fi first
#define se second
#define all(v) (v).begin(), (v).end()
#define fillchar(a, s) memset((a), (s), sizeof(a))

int N, C, Q;
int T[MAXN], X[MAXN], Y[MAXN];	//Edges
int E[MAXN];	//edge ID.
int W[MAXN], P[MAXN];	//Queries
int ans[MAXN];

struct union_find {
	int par[MAXN];
	stack<pair<int*, int>> chng;	//god fucking damn it. used vector not stack. Then used a "forall" loop on it. But you need to go backward NOT forward iterating through this container!!!
	bool active;
	int ncomp;

	void reset() {
		for (int i = 0; i < N; i++) {
			par[i] = i;
		}
		ncomp = N;
		assert(chng.empty());
		active = false;
	}

	void change (int &x, int y) {
		if (active) {
			chng.push(make_pair(&x, x));
		}
		x = y;
	}

	int find (int x) {
		if (x == par[x]) {
			return x;
		}
		change(par[x], find(par[x]));
		return par[x];
	}

	void merge (int x, int y) {
		x = find(x);
		y = find(y);
		if (x == y) {
			return;
		}
		change(par[x], y);
		change(ncomp, ncomp - 1);
	}

	void rollback() {
		while (!chng.empty()) {
			*(chng.top().fi) = chng.top().se;
			chng.pop();
		}
	}
};

int death[MAXN];	//death time of edge.
vector<pii> queries[MAXN];	//queries[day] = vector(position, id)
union_find uf;
int estl[MAXN], estr[MAXN], tmp[MAXN];

bool cmpr (int a, int b) {
	return Y[a] < Y[b];
}

bool cmpl (int a, int b) {
	return X[a] > X[b];
}

void solve() {
	//X, Y = roads constructed
	//w, P = questions.
	/*
	//they aren't vectors but global arrays.
	assert(X.size() == C);
	assert(Y.size() == C);
	assert(W.size() == Q);
	assert(P.size() == Q);
	*/

	for (int i = 0; i < Q; i++) {
		queries[W[i]].push_back({P[i], i});
	}

	for (int sday = 0; sday < C; sday += SQRT) {
		int eday = min(sday + SQRT, C);
		//what is the stuff before sday? certainly need to add this in.
		vector<array<int, 3>> vqu;
		for (int i = sday; i < eday; i++) {
			for (pii p : queries[i]) {
				vqu.push_back({p.fi, i, p.se});
			}
		}

		//ok let's now go to this now.

		int posr = 0;	//position of estr
		//prefix
		debug("-------start prefix----------\n");
		
		sort(all(vqu));
		uf.reset();

		//preliminary add edge if: it is born before sday (edgeid < sday) and if it dies >= eday (death[edgeid] >= eday)
		for (auto q : vqu) {
			int pos = q[0];
			for (; posr < sday && Y[estr[posr]] <= q[0]; posr++) {
				int edgeid = estr[posr];
				debug("death[%d] = %d\n", edgeid, eday);
				assert(death[edgeid] >= eday);
				if (edgeid < sday && death[edgeid] >= eday) {
					uf.merge(X[edgeid], Y[edgeid]);
					debug("merge %d %d\n", X[edgeid], Y[edgeid]);
				}
			}

			//need this
			for (int i = sday; i < eday; i++) {
				uf.find(X[i]);
				uf.find(Y[i]);
			}

			uf.active = true;
			debug("--active--\n");
			//then merge the rest of them!
			for (int i = sday; i <= q[1]; i++) {
				//is this a valid merge?
				debug("Start with ncomp = %d\n", uf.ncomp);
				if (Y[i] <= pos) {
					debug("find(1) == find(56)? %d. find(60) == find(72)? %d.\n", (uf.find(1) == uf.find(56)), (uf.find(60) == uf.find(72)));	//this is for the specific test data in "cbad.in" - it gets 36 not 35 in original buggy code for the first query (35 is correct answer)

					//only add edge if: born <= q[1] (edgeid <= q[1]) -- this is actually 100% going to happen here -- and not dead yet (death[edgeid] > q[1])
					int edgeid = E[i];
					assert(edgeid <= q[1]);
					if (death[edgeid] > q[1]) {
						uf.merge(X[i], Y[i]);
						debug("merge %d %d\n", X[i], Y[i]);
					}
				}
			}

			ans[q[2]] += uf.ncomp;
			debug("answer[%d] += %d\n", q[2], uf.ncomp);
			uf.rollback();
			uf.active = false;
			debug("--inactive--\n");
		}

		debug("-------start suffix----------\n");
		//suffix

		uf.reset();
		reverse(all(vqu));

		int posl = 0;
		for (auto q : vqu) {
			int pos = q[0];
			//note: strictly greater than q[0]
			for (; posl < sday && X[estl[posl]] > q[0]; posl++) {
				int edgeid = estl[posl];
				if (edgeid < sday && death[edgeid] >= eday) {
					uf.merge(X[edgeid], Y[edgeid]);
					debug("merge %d %d\n", X[edgeid], Y[edgeid]);
				}

			}
			//need this
			for (int i = sday; i < eday; i++) {
				uf.find(X[i]);
				uf.find(Y[i]);
			}

			debug("--active--\n");
			uf.active = true;
			for (int i = sday; i <= q[1]; i++) {
				if (X[i] > pos) {
					int edgeid = E[i];
					if (death[edgeid] > q[1]) {
						uf.merge(X[i], Y[i]);
						debug("merge %d %d\n", X[i], Y[i]);
					}
				}
			}

			ans[q[2]] += uf.ncomp - N;
			debug("answer[%d] += %d; answer[%d] -= N\n", q[2], uf.ncomp, q[2]);
			uf.rollback();
			debug("--inactive--\n");
			uf.active = false;
		}


		//then add the new edges
		vector<int> nedge;
		for (int i = sday; i < eday; i++) {
			nedge.push_back(i);
		}
		sort(all(nedge), cmpl);
		copy(tmp, merge(estl, estl + sday, all(nedge), tmp, cmpl), estl);
		sort(all(nedge), cmpr);
		copy(tmp, merge(estr, estr + sday, all(nedge), tmp, cmpr), estr);
	}
}

vector<int> simulateCollapse (int n, vector<int> ttt, vector<int> xxx, vector<int> yyy, vector<int> www, vector<int> ppp) {
	//globalize the variables
	N = n;
	C = xxx.size();
	Q = www.size();
	for (int i = 0; i < C; i++) {
		T[i] = ttt[i];
		X[i] = xxx[i];
		Y[i] = yyy[i];
	}
	for (int i = 0; i < Q; i++) {
		W[i] = www[i];
		P[i] = ppp[i];
	}

	map<pii, vector<int>> mpind;
	for (int i = 0; i < C; i++) {
		if (X[i] > Y[i]) {
			swap(X[i], Y[i]);
		}
		pii p(X[i], Y[i]);
		if (T[i] == 1) {
			//remove it
			int ind = mpind.at(p).back();
			death[ind] = i;
			E[i] = ind;
			mpind.at(p).pop_back();
		} else {
			death[i] = C;
			E[i] = i;
			mpind[p].push_back(i);
		}
	}

	solve();
	return vector<int> (ans, ans + Q);
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 30
• Subtask 3: 30 / 30
• Subtask 4: 0 / 35