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답안 #384153

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
384153 2021-03-31T14:46:57 Z dapig Network (BOI15_net) C++11
100 / 100
 919 ms 63364 KB 
#include <cstdio>
#include <iostream> 
#include <vector>
#include <queue>
#include <algorithm>
#include <set>
#include <map>
#include <utility>

using namespace std;

int n;
vector<int> graph[500005];
int start;
	
	int leaves[500005];
	int et[500005]; int marker = 0;
	int etrev[500005];
	
int bit[500005];
void upd(int n, int inc) {
	n++;
	while (n < 500005) {
			bit[n] += inc;
			n += (n&-n);
		}
	}
	int find(int n) {
		int s = 0;
		n++;
		while (n > 0) {
			s += bit[n];
			n -= (n&-n);
		}
		return s;
	}
	int findfirst(int n) {
		if (graph[n].size()==1) return etrev[n];
		int l = 0, r = 500005, v = find(etrev[n]);
		int best = 500004;
		while (l < r) {
			int m = (l+r)/2;
			if (find(m) > v) {
				best = m; r = m;
			} else l = m+1;
		}
		return best;
	}
	int leaffind(int n, int p) {
		et[marker] = n; marker++;
		etrev[et[marker-1]] = marker-1;
		int vis = 0;
		for (int i : graph[n]) {
			if (i == p) continue;
			vis += leaffind(i, n);
		}
		if (vis == 0) {
			leaves[n] = 1;
			upd(marker-1, 1);
			return 1;
		}
		leaves[n] = vis;
		return vis;
	}
	
	vector<pair<int, int>> pairs;
	void findans(int n, int p, int reps) {
		int max = 0, pos = 0, sum = 0;
		for (int i : graph[n]) {
			if (i == p) continue;
			sum += leaves[i];
			if (leaves[i] > max) {
				max = leaves[i];
				pos = i;
			}
		}
		int pairable = min(sum, (sum-max)*2);
		if (reps > pairable) {
			findans(pos, n, reps-pairable);
			leaves[pos] = sum-max;
			reps -= (reps-pairable);
		}
		/*
		PriorityQueue<int[]> pq = new PriorityQueue<>(new SortArr());
		for (int i : graph[n]) {
			if (i == p) continue;
			pq.add(new int[] {i, leaves[i]});
		}
		
		while (reps > 1) {
			int[] data1 = pq.poll();
			int[] data2 = pq.poll();
			int pos1 = findfirst(data1[0]);
			int pos2 = findfirst(data2[0]);
			upd(pos1, -1); upd(pos2, -1);
			pairs.add(new int[] {et[pos1]+1, et[pos2]+1});
			if (data1[1] > 1) pq.add(new int[] {data1[0], data1[1]-1});
			if (data2[1] > 1) pq.add(new int[] {data2[0], data2[1]-1});
			reps -= 2;
		}
		
		if (reps == 1) {
			int[] data1 = pq.poll();
			int pos1 = findfirst(data1[0]);
			upd(pos1, -1);
			pairs.add(new int[] {et[pos1]+1, n+1});
		}*/
		int maxleaves = 0;
		for (int i : graph[n]) {
			if (i==p) continue;
			maxleaves = std::max(maxleaves, leaves[i]);
		}
		vector<int> stack[maxleaves+1];
		for (int i = 0; i < maxleaves+1; i++) {
			vector<int> temp;
            stack[i] = temp;
		}
		max = 0; int max2 = 0;
		for (int i : graph[n]) {
			if (i==p) continue;
			stack[leaves[i]].push_back(i);
			if (leaves[i] > max) {
				max2 = max; max = leaves[i];
			} else if (leaves[i] > max2) max2 = leaves[i];
		}
		while (reps > 1) {
			pair<int, int> data1{stack[max].back(), max};
			stack[max].pop_back();
			pair<int, int> data2{stack[max2].back(), max2};
            stack[max2].pop_back();
			int pos1 = findfirst(data1.first);
			int pos2 = findfirst(data2.first);
			upd(pos1, -1); upd(pos2, -1);
			pairs.push_back({et[pos1]+1, et[pos2]+1});
			if (data1.second > 1) {
				stack[data1.second-1].push_back(data1.first);
			}
			if (data2.second > 1) {
				stack[data2.second-1].push_back(data2.first);
			}
			if (stack[max].size() == 0) max--;
			if (stack[max2].size() == 0) max2--;
			if (max2 == max && stack[max].size() == 1) max2--;
			reps -= 2;
		}
		if (reps == 1) {
			pair<int, int> data1{stack[max].back(), max};
            stack[max].pop_back();
			int pos1 = findfirst(data1.first);
			upd(pos1, -1);
			pairs.push_back({et[pos1]+1, n+1});
		}
	}
	
	int main() {

		cin >> n;
		for (int i = 0; i < 500005; i++) {
            vector<int> temp;
			graph[i] = temp;
		}
		for (int i = 0; i < n-1; i++) {
			int a, b; cin >> a >> b; a--; b--;
			graph[a].push_back(b);
			graph[b].push_back(a);
		}
		
		for (int i = 0; i < 500005; i++) {
			if (graph[i].size() > 1) {
				start = i; break;
			}
		}
		leaffind(start, -1);
		findans(start, -1, leaves[start]);
		cout << (pairs.size()) << "\n";
		for (pair<int, int> i : pairs) {
			cout << (i.first) << " " << (i.second) << "\n";
		}

	}

Subtask #1
18.0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 12140 KB Output is correct
2 Correct 12 ms 12140 KB Output is correct
3 Correct 12 ms 12140 KB Output is correct
4 Correct 12 ms 12140 KB Output is correct
5 Correct 12 ms 12140 KB Output is correct
6 Correct 12 ms 12140 KB Output is correct
7 Correct 12 ms 12140 KB Output is correct
8 Correct 12 ms 12140 KB Output is correct
9 Correct 12 ms 12140 KB Output is correct
10 Correct 13 ms 12140 KB Output is correct
11 Correct 12 ms 12140 KB Output is correct
12 Correct 12 ms 12140 KB Output is correct
13 Correct 15 ms 12140 KB Output is correct
14 Correct 12 ms 12140 KB Output is correct
15 Correct 13 ms 12140 KB Output is correct
16 Correct 12 ms 12140 KB Output is correct
17 Correct 12 ms 12140 KB Output is correct
18 Correct 12 ms 12140 KB Output is correct
19 Correct 12 ms 12160 KB Output is correct
20 Correct 12 ms 12140 KB Output is correct

Subtask #2
45.0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 12140 KB Output is correct
2 Correct 12 ms 12140 KB Output is correct
3 Correct 12 ms 12140 KB Output is correct
4 Correct 12 ms 12140 KB Output is correct
5 Correct 12 ms 12140 KB Output is correct
6 Correct 12 ms 12140 KB Output is correct
7 Correct 12 ms 12140 KB Output is correct
8 Correct 12 ms 12140 KB Output is correct
9 Correct 12 ms 12140 KB Output is correct
10 Correct 13 ms 12140 KB Output is correct
11 Correct 12 ms 12140 KB Output is correct
12 Correct 12 ms 12140 KB Output is correct
13 Correct 15 ms 12140 KB Output is correct
14 Correct 12 ms 12140 KB Output is correct
15 Correct 13 ms 12140 KB Output is correct
16 Correct 12 ms 12140 KB Output is correct
17 Correct 12 ms 12140 KB Output is correct
18 Correct 12 ms 12140 KB Output is correct
19 Correct 12 ms 12160 KB Output is correct
20 Correct 12 ms 12140 KB Output is correct
21 Correct 12 ms 12140 KB Output is correct
22 Correct 14 ms 12268 KB Output is correct
23 Correct 14 ms 12268 KB Output is correct
24 Correct 15 ms 12268 KB Output is correct
25 Correct 14 ms 12268 KB Output is correct
26 Correct 14 ms 12268 KB Output is correct
27 Correct 15 ms 12268 KB Output is correct
28 Correct 14 ms 12268 KB Output is correct
29 Correct 14 ms 12268 KB Output is correct
30 Correct 13 ms 12140 KB Output is correct
31 Correct 17 ms 12268 KB Output is correct
32 Correct 12 ms 12140 KB Output is correct
33 Correct 12 ms 12140 KB Output is correct
34 Correct 12 ms 12140 KB Output is correct
35 Correct 12 ms 12140 KB Output is correct
36 Correct 12 ms 12140 KB Output is correct
37 Correct 13 ms 12140 KB Output is correct
38 Correct 13 ms 12268 KB Output is correct
39 Correct 12 ms 12140 KB Output is correct
40 Correct 12 ms 12140 KB Output is correct
41 Correct 13 ms 12140 KB Output is correct
42 Correct 13 ms 12140 KB Output is correct
43 Correct 13 ms 12140 KB Output is correct
44 Correct 13 ms 12140 KB Output is correct
45 Correct 13 ms 12140 KB Output is correct
46 Correct 13 ms 12140 KB Output is correct
47 Correct 12 ms 12128 KB Output is correct
48 Correct 12 ms 12140 KB Output is correct
49 Correct 14 ms 12268 KB Output is correct
50 Correct 16 ms 12140 KB Output is correct
51 Correct 12 ms 12140 KB Output is correct
52 Correct 13 ms 12140 KB Output is correct
53 Correct 13 ms 12140 KB Output is correct
54 Correct 12 ms 12176 KB Output is correct
55 Correct 13 ms 12140 KB Output is correct
56 Correct 13 ms 12140 KB Output is correct
57 Correct 14 ms 12140 KB Output is correct
58 Correct 14 ms 12268 KB Output is correct

Subtask #3
37.0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 12140 KB Output is correct
2 Correct 12 ms 12140 KB Output is correct
3 Correct 12 ms 12140 KB Output is correct
4 Correct 12 ms 12140 KB Output is correct
5 Correct 12 ms 12140 KB Output is correct
6 Correct 12 ms 12140 KB Output is correct
7 Correct 12 ms 12140 KB Output is correct
8 Correct 12 ms 12140 KB Output is correct
9 Correct 12 ms 12140 KB Output is correct
10 Correct 13 ms 12140 KB Output is correct
11 Correct 12 ms 12140 KB Output is correct
12 Correct 12 ms 12140 KB Output is correct
13 Correct 15 ms 12140 KB Output is correct
14 Correct 12 ms 12140 KB Output is correct
15 Correct 13 ms 12140 KB Output is correct
16 Correct 12 ms 12140 KB Output is correct
17 Correct 12 ms 12140 KB Output is correct
18 Correct 12 ms 12140 KB Output is correct
19 Correct 12 ms 12160 KB Output is correct
20 Correct 12 ms 12140 KB Output is correct
21 Correct 12 ms 12140 KB Output is correct
22 Correct 14 ms 12268 KB Output is correct
23 Correct 14 ms 12268 KB Output is correct
24 Correct 15 ms 12268 KB Output is correct
25 Correct 14 ms 12268 KB Output is correct
26 Correct 14 ms 12268 KB Output is correct
27 Correct 15 ms 12268 KB Output is correct
28 Correct 14 ms 12268 KB Output is correct
29 Correct 14 ms 12268 KB Output is correct
30 Correct 13 ms 12140 KB Output is correct
31 Correct 17 ms 12268 KB Output is correct
32 Correct 12 ms 12140 KB Output is correct
33 Correct 12 ms 12140 KB Output is correct
34 Correct 12 ms 12140 KB Output is correct
35 Correct 12 ms 12140 KB Output is correct
36 Correct 12 ms 12140 KB Output is correct
37 Correct 13 ms 12140 KB Output is correct
38 Correct 13 ms 12268 KB Output is correct
39 Correct 12 ms 12140 KB Output is correct
40 Correct 12 ms 12140 KB Output is correct
41 Correct 13 ms 12140 KB Output is correct
42 Correct 13 ms 12140 KB Output is correct
43 Correct 13 ms 12140 KB Output is correct
44 Correct 13 ms 12140 KB Output is correct
45 Correct 13 ms 12140 KB Output is correct
46 Correct 13 ms 12140 KB Output is correct
47 Correct 12 ms 12128 KB Output is correct
48 Correct 12 ms 12140 KB Output is correct
49 Correct 14 ms 12268 KB Output is correct
50 Correct 16 ms 12140 KB Output is correct
51 Correct 12 ms 12140 KB Output is correct
52 Correct 13 ms 12140 KB Output is correct
53 Correct 13 ms 12140 KB Output is correct
54 Correct 12 ms 12176 KB Output is correct
55 Correct 13 ms 12140 KB Output is correct
56 Correct 13 ms 12140 KB Output is correct
57 Correct 14 ms 12140 KB Output is correct
58 Correct 14 ms 12268 KB Output is correct
59 Correct 776 ms 38796 KB Output is correct
60 Correct 896 ms 51564 KB Output is correct
61 Correct 12 ms 12140 KB Output is correct
62 Correct 12 ms 12140 KB Output is correct
63 Correct 700 ms 41288 KB Output is correct
64 Correct 16 ms 12780 KB Output is correct
65 Correct 33 ms 14700 KB Output is correct
66 Correct 264 ms 36328 KB Output is correct
67 Correct 744 ms 57324 KB Output is correct
68 Correct 775 ms 60312 KB Output is correct
69 Correct 26 ms 13292 KB Output is correct
70 Correct 205 ms 24432 KB Output is correct
71 Correct 665 ms 49876 KB Output is correct
72 Correct 690 ms 48788 KB Output is correct
73 Correct 200 ms 22500 KB Output is correct
74 Correct 858 ms 50272 KB Output is correct
75 Correct 74 ms 17256 KB Output is correct
76 Correct 762 ms 62396 KB Output is correct
77 Correct 748 ms 63364 KB Output is correct
78 Correct 70 ms 17004 KB Output is correct
79 Correct 757 ms 54892 KB Output is correct
80 Correct 16 ms 12396 KB Output is correct
81 Correct 256 ms 25624 KB Output is correct
82 Correct 814 ms 51628 KB Output is correct
83 Correct 859 ms 48992 KB Output is correct
84 Correct 851 ms 47732 KB Output is correct
85 Correct 847 ms 49288 KB Output is correct
86 Correct 919 ms 53768 KB Output is correct
87 Correct 903 ms 53792 KB Output is correct