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Submission #541905

# Submission time Handle Problem Language Result Execution time Memory
541905 2022-03-24T18:53:24 Z Asymmetry Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 937 ms 215632 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 stp[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);
		++stp[a];
		++stp[b];
	}
	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 = max(n, 40), 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:61:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |  scanf("%d%d%d", &n, &q, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:63:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |   scanf("%d%d", &a, &b);
      |   ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23848 KB Output is correct
3 Correct 11 ms 23820 KB Output is correct
4 Correct 12 ms 23800 KB Output is correct
5 Correct 11 ms 23724 KB Output is correct
6 Correct 11 ms 23728 KB Output is correct
7 Correct 14 ms 23820 KB Output is correct
8 Correct 11 ms 23764 KB Output is correct
9 Correct 11 ms 23764 KB Output is correct
10 Correct 11 ms 23764 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 375 ms 66880 KB Output is correct
2 Correct 348 ms 62532 KB Output is correct
3 Correct 890 ms 68048 KB Output is correct
4 Correct 464 ms 45936 KB Output is correct
5 Correct 874 ms 67992 KB Output is correct
6 Correct 867 ms 67972 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23848 KB Output is correct
3 Correct 11 ms 23820 KB Output is correct
4 Correct 12 ms 23800 KB Output is correct
5 Correct 11 ms 23724 KB Output is correct
6 Correct 11 ms 23728 KB Output is correct
7 Correct 14 ms 23820 KB Output is correct
8 Correct 11 ms 23764 KB Output is correct
9 Correct 11 ms 23764 KB Output is correct
10 Correct 11 ms 23764 KB Output is correct
11 Correct 12 ms 23764 KB Output is correct
12 Correct 12 ms 23904 KB Output is correct
13 Correct 12 ms 23892 KB Output is correct
14 Correct 13 ms 23984 KB Output is correct
15 Correct 13 ms 23996 KB Output is correct
16 Correct 13 ms 23892 KB Output is correct
17 Correct 13 ms 23892 KB Output is correct
18 Correct 13 ms 23868 KB Output is correct
19 Correct 15 ms 23892 KB Output is correct
20 Correct 12 ms 23892 KB Output is correct
21 Correct 13 ms 23892 KB Output is correct
22 Correct 12 ms 23840 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23848 KB Output is correct
3 Correct 11 ms 23820 KB Output is correct
4 Correct 12 ms 23800 KB Output is correct
5 Correct 11 ms 23724 KB Output is correct
6 Correct 11 ms 23728 KB Output is correct
7 Correct 14 ms 23820 KB Output is correct
8 Correct 11 ms 23764 KB Output is correct
9 Correct 11 ms 23764 KB Output is correct
10 Correct 11 ms 23764 KB Output is correct
11 Correct 375 ms 66880 KB Output is correct
12 Correct 348 ms 62532 KB Output is correct
13 Correct 890 ms 68048 KB Output is correct
14 Correct 464 ms 45936 KB Output is correct
15 Correct 874 ms 67992 KB Output is correct
16 Correct 867 ms 67972 KB Output is correct
17 Correct 12 ms 23764 KB Output is correct
18 Correct 12 ms 23904 KB Output is correct
19 Correct 12 ms 23892 KB Output is correct
20 Correct 13 ms 23984 KB Output is correct
21 Correct 13 ms 23996 KB Output is correct
22 Correct 13 ms 23892 KB Output is correct
23 Correct 13 ms 23892 KB Output is correct
24 Correct 13 ms 23868 KB Output is correct
25 Correct 15 ms 23892 KB Output is correct
26 Correct 12 ms 23892 KB Output is correct
27 Correct 13 ms 23892 KB Output is correct
28 Correct 12 ms 23840 KB Output is correct
29 Correct 11 ms 23848 KB Output is correct
30 Correct 370 ms 66872 KB Output is correct
31 Correct 366 ms 66916 KB Output is correct
32 Correct 548 ms 215632 KB Output is correct
33 Correct 451 ms 207776 KB Output is correct
34 Correct 889 ms 68032 KB Output is correct
35 Correct 879 ms 67964 KB Output is correct
36 Correct 888 ms 82740 KB Output is correct
37 Correct 937 ms 82820 KB Output is correct
38 Correct 712 ms 85420 KB Output is correct
39 Correct 729 ms 85348 KB Output is correct
40 Correct 691 ms 85504 KB Output is correct