Submission #136438

#	Time	Username	Problem	Language	Result	Execution time	Memory
136438		imyujin	Link (CEOI06_link)	C++14	72 / 100	1578 ms	25820 KiB

link

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

const int MAXN = 500005;
const int MAXK = 20005;

int A[MAXN], B[MAXN];
int ed[MAXN], ind[MAXN];
bool chk[MAXN], on[MAXN], cyc[MAXN];
vector<int> cnod[MAXN];
int cn;
queue<int> indz;

void searchgraph(int x) {
	//printf("searchgraph(%d)\n", x);
	chk[x] = on[x] = true;
	if(on[ed[x]]) {
		for(int t = x; !cyc[t]; t = ed[t]) {
			cyc[t] = true;
			cnod[cn].push_back(t);
		}
		cn++;
	}
	else if(!chk[ed[x]]) searchgraph(ed[x]);
	on[x] = false;
}

void movek(int x, int k) {
	for(; k-- >= 0; x = ed[x]) chk[x] = true;
	if(--ind[x] == 0) indz.push(x);
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	int N, K;
	int ans = 0;

	cin >> N >> K;
	for(int i = 0; i < N; i++) cin >> A[i] >> B[i];

	for(int i = 0; i < N; i++) {
		ed[A[i]] = B[i];
		ind[B[i]]++;
	}

	for(int i = 1; i <= N; i++) if(!chk[i]) searchgraph(i);
	//printf("cn = %d\n", cn);
	//for(auto a : cnod[0]) printf("%d ", a);
	//printf("\n");
	for(int i = 1; i <= N; i++) chk[i] = false;
	movek(1, K);
	for(int i = 1; i <= N; i++) if(ind[i] == 0) indz.push(i);
	while(!indz.empty()) {
		if(!chk[indz.front()] && !cyc[indz.front()]) {
			//printf("indz = %d\n", indz.front());
			movek(indz.front(), K - 1);
			ans++;
		}
		indz.pop();
	}
	//for(int i = 1; i <= N; i++) printf("%d ", int(chk[i]));
	//printf("\nans = %d\n", ans);

	for(int i = 0; i < cn; i++) {
		//for(auto a : cnod[i]) printf("%d ", a);
		//printf("\n");
		bool done = true;
		for(auto a : cnod[i]) done &= chk[a];
		if(done) continue;
		if(cnod[i].size() <= K) {
			ans++;
			continue;
		}
		int mn = cnod[i].size();
		for(int j = 0; j < cnod[i].size(); j++) {
			int cnt = 0, t = j;
			while(t < cnod[i].size() + j) {
				while(t < cnod[i].size() + j && chk[cnod[i][t % cnod[i].size()]]) t++;
				if(t == cnod[i].size() + j) break;
				cnt++;
				t += K;
			}
			mn = min(mn, cnt);
		}
		ans += mn;
	}

	cout << ans;
	return 0;
}

Compilation message (stderr)

link.cpp: In function 'int main()':
link.cpp:70:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(cnod[i].size() <= K) {
      ~~~~~~~~~~~~~~~^~~~
link.cpp:75:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < cnod[i].size(); j++) {
                  ~~^~~~~~~~~~~~~~~~
link.cpp:77:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(t < cnod[i].size() + j) {
          ~~^~~~~~~~~~~~~~~~~~~~
link.cpp:78:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(t < cnod[i].size() + j && chk[cnod[i][t % cnod[i].size()]]) t++;
           ~~^~~~~~~~~~~~~~~~~~~~
link.cpp:79:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(t == cnod[i].size() + j) break;
        ~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 72 / 100