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Submission #541908

# Submission time Handle Problem Language Result Execution time Memory
541908 2022-03-24T18:55:20 Z Asymmetry Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 901 ms 211664 KB 
//Autor: Bartłomiej Czarkowski
#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
template<class A,class B>auto&operator<<(ostream&o,pair<A,B>p){return o<<'('<<p.first<<", "<<p.second<<')';}
template<class T>auto operator<<(ostream&o,T x)->decltype(x.end(),o){o<<'{';int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<'}';}
#define debug(x...) cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...);}(x),cerr<<'\n'
#else
#define debug(...) {}
#endif

const int N = 1001000;
int n, a, b, m, q;
int par[N];
int son[N];
int cost[N];
int blk[N];
int dp[N]; // ile żeby uwięzić i wyprowadzić do ojca
vector<int> v[N];

void dfs_dp(int x) {
	vector<int> war = {0, 0};
	for (int i : v[x]) {
		if (i == par[x]) {
			continue;
		}
		par[i] = x;
		dfs_dp(i);
		war.push_back(dp[i]);
	}
	nth_element(war.begin(), war.begin() + 1, war.end(), [&](int a, int b) {
		return a > b;
	});
	dp[x] = war[1] + war.size() - 2;
}

bool check(int wyn) {
	int x = m, nad = 1, usd = 0;
	while (x != q) {
		int ile = 0;
		for (int i : v[x]) {
			if (i != par[x] && i != son[x]) {
				if (dp[i] + blk[x] + usd > wyn) {
					++ile;
				}
			}
		}
		if (ile > nad) {
			return false;
		}
		nad -= ile;
		usd += ile;
		x = par[x];
		++nad;
	}
	return usd <= wyn;
}

int main() {
	scanf("%d%d%d", &n, &q, &m);
	for (int i = 1; i < n; ++i) {
		scanf("%d%d", &a, &b);
		v[a].push_back(b);
		v[b].push_back(a);
	}
	dfs_dp(q);
	int x = m;
	while (x != q) {
		son[par[x]] = x;
		x = par[x];
	}
	while (x != m) {
		x = son[x];
		blk[x] = blk[par[x]];
		for (int i : v[x]) {
			blk[x] += (i != par[x]) && (i != son[x]);
		}
	}
	int bp = -1, bk = n, bs;
	while (bk - bp > 1) {
		bs = (bp + bk) / 2;
		if (check(bs)) {
			bk = bs;
		}
		else {
			bp = bs;
		}
	}
	printf("%d\n", bk);
	return 0;
}

Compilation message

mousetrap.cpp: In function 'int main()':
mousetrap.cpp:60:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |  scanf("%d%d%d", &n, &q, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:62:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |   scanf("%d%d", &a, &b);
      |   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 11 ms 23764 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 11 ms 23824 KB Output is correct
6 Correct 12 ms 23784 KB Output is correct
7 Correct 13 ms 23744 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 371 ms 63060 KB Output is correct
2 Correct 335 ms 58960 KB Output is correct
3 Correct 865 ms 64160 KB Output is correct
4 Correct 384 ms 43936 KB Output is correct
5 Correct 825 ms 64040 KB Output is correct
6 Correct 835 ms 64048 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 11 ms 23764 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 11 ms 23824 KB Output is correct
6 Correct 12 ms 23784 KB Output is correct
7 Correct 13 ms 23744 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct
11 Correct 14 ms 23764 KB Output is correct
12 Correct 12 ms 23764 KB Output is correct
13 Correct 12 ms 23808 KB Output is correct
14 Correct 12 ms 23996 KB Output is correct
15 Correct 12 ms 23964 KB Output is correct
16 Correct 14 ms 23780 KB Output is correct
17 Correct 13 ms 23764 KB Output is correct
18 Correct 13 ms 23892 KB Output is correct
19 Correct 13 ms 23860 KB Output is correct
20 Correct 12 ms 23892 KB Output is correct
21 Correct 13 ms 23828 KB Output is correct
22 Correct 16 ms 23872 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 23764 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 11 ms 23764 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 11 ms 23824 KB Output is correct
6 Correct 12 ms 23784 KB Output is correct
7 Correct 13 ms 23744 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct
11 Correct 371 ms 63060 KB Output is correct
12 Correct 335 ms 58960 KB Output is correct
13 Correct 865 ms 64160 KB Output is correct
14 Correct 384 ms 43936 KB Output is correct
15 Correct 825 ms 64040 KB Output is correct
16 Correct 835 ms 64048 KB Output is correct
17 Correct 14 ms 23764 KB Output is correct
18 Correct 12 ms 23764 KB Output is correct
19 Correct 12 ms 23808 KB Output is correct
20 Correct 12 ms 23996 KB Output is correct
21 Correct 12 ms 23964 KB Output is correct
22 Correct 14 ms 23780 KB Output is correct
23 Correct 13 ms 23764 KB Output is correct
24 Correct 13 ms 23892 KB Output is correct
25 Correct 13 ms 23860 KB Output is correct
26 Correct 12 ms 23892 KB Output is correct
27 Correct 13 ms 23828 KB Output is correct
28 Correct 16 ms 23872 KB Output is correct
29 Correct 12 ms 23840 KB Output is correct
30 Correct 388 ms 62956 KB Output is correct
31 Correct 362 ms 62944 KB Output is correct
32 Correct 532 ms 211664 KB Output is correct
33 Correct 444 ms 203820 KB Output is correct
34 Correct 836 ms 64108 KB Output is correct
35 Correct 834 ms 64048 KB Output is correct
36 Correct 901 ms 78768 KB Output is correct
37 Correct 883 ms 78880 KB Output is correct
38 Correct 713 ms 81464 KB Output is correct
39 Correct 753 ms 81492 KB Output is correct
40 Correct 741 ms 81548 KB Output is correct