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Submission #541904

# Submission time Handle Problem Language Result Execution time Memory
541904 2022-03-24T18:52:22 Z Asymmetry Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 1038 ms 224068 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, 1000), 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 13 ms 23764 KB Output is correct
2 Correct 13 ms 23816 KB Output is correct
3 Correct 15 ms 23796 KB Output is correct
4 Correct 15 ms 23840 KB Output is correct
5 Correct 13 ms 23764 KB Output is correct
6 Correct 12 ms 23764 KB Output is correct
7 Correct 14 ms 23776 KB Output is correct
8 Correct 13 ms 23736 KB Output is correct
9 Correct 13 ms 23764 KB Output is correct
10 Correct 15 ms 23748 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 393 ms 70460 KB Output is correct
2 Correct 357 ms 65820 KB Output is correct
3 Correct 1008 ms 71424 KB Output is correct
4 Correct 435 ms 50256 KB Output is correct
5 Correct 972 ms 71524 KB Output is correct
6 Correct 975 ms 71512 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 13 ms 23816 KB Output is correct
3 Correct 15 ms 23796 KB Output is correct
4 Correct 15 ms 23840 KB Output is correct
5 Correct 13 ms 23764 KB Output is correct
6 Correct 12 ms 23764 KB Output is correct
7 Correct 14 ms 23776 KB Output is correct
8 Correct 13 ms 23736 KB Output is correct
9 Correct 13 ms 23764 KB Output is correct
10 Correct 15 ms 23748 KB Output is correct
11 Correct 13 ms 23764 KB Output is correct
12 Correct 13 ms 23868 KB Output is correct
13 Correct 13 ms 23820 KB Output is correct
14 Correct 12 ms 23952 KB Output is correct
15 Correct 13 ms 24020 KB Output is correct
16 Correct 13 ms 23764 KB Output is correct
17 Correct 14 ms 23892 KB Output is correct
18 Correct 15 ms 23824 KB Output is correct
19 Correct 13 ms 23892 KB Output is correct
20 Correct 13 ms 23816 KB Output is correct
21 Correct 13 ms 23828 KB Output is correct
22 Correct 13 ms 23836 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 13 ms 23816 KB Output is correct
3 Correct 15 ms 23796 KB Output is correct
4 Correct 15 ms 23840 KB Output is correct
5 Correct 13 ms 23764 KB Output is correct
6 Correct 12 ms 23764 KB Output is correct
7 Correct 14 ms 23776 KB Output is correct
8 Correct 13 ms 23736 KB Output is correct
9 Correct 13 ms 23764 KB Output is correct
10 Correct 15 ms 23748 KB Output is correct
11 Correct 393 ms 70460 KB Output is correct
12 Correct 357 ms 65820 KB Output is correct
13 Correct 1008 ms 71424 KB Output is correct
14 Correct 435 ms 50256 KB Output is correct
15 Correct 972 ms 71524 KB Output is correct
16 Correct 975 ms 71512 KB Output is correct
17 Correct 13 ms 23764 KB Output is correct
18 Correct 13 ms 23868 KB Output is correct
19 Correct 13 ms 23820 KB Output is correct
20 Correct 12 ms 23952 KB Output is correct
21 Correct 13 ms 24020 KB Output is correct
22 Correct 13 ms 23764 KB Output is correct
23 Correct 14 ms 23892 KB Output is correct
24 Correct 15 ms 23824 KB Output is correct
25 Correct 13 ms 23892 KB Output is correct
26 Correct 13 ms 23816 KB Output is correct
27 Correct 13 ms 23828 KB Output is correct
28 Correct 13 ms 23836 KB Output is correct
29 Correct 13 ms 23820 KB Output is correct
30 Correct 397 ms 75640 KB Output is correct
31 Correct 405 ms 75636 KB Output is correct
32 Correct 571 ms 224068 KB Output is correct
33 Correct 567 ms 216204 KB Output is correct
34 Correct 958 ms 76444 KB Output is correct
35 Correct 973 ms 76540 KB Output is correct
36 Correct 996 ms 91156 KB Output is correct
37 Correct 1038 ms 91308 KB Output is correct
38 Correct 764 ms 93880 KB Output is correct
39 Correct 778 ms 88648 KB Output is correct
40 Correct 767 ms 88748 KB Output is correct