oj.uz

Submission #535526

# Submission time Handle Problem Language Result Execution time Memory
535526 2022-03-10T12:47:09 Z Asymmetry Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 1037 ms 229072 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;
//~ const int N = 1010;
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 = 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:62:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |  scanf("%d%d%d", &n, &q, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:64:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |   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 23856 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 13 ms 23764 KB Output is correct
5 Correct 15 ms 23764 KB Output is correct
6 Correct 12 ms 23832 KB Output is correct
7 Correct 13 ms 23828 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 15 ms 23764 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 373 ms 66896 KB Output is correct
2 Correct 345 ms 62468 KB Output is correct
3 Correct 947 ms 67968 KB Output is correct
4 Correct 409 ms 45908 KB Output is correct
5 Correct 989 ms 68060 KB Output is correct
6 Correct 968 ms 68104 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 23856 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 13 ms 23764 KB Output is correct
5 Correct 15 ms 23764 KB Output is correct
6 Correct 12 ms 23832 KB Output is correct
7 Correct 13 ms 23828 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 15 ms 23764 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Correct 12 ms 23840 KB Output is correct
12 Correct 12 ms 23832 KB Output is correct
13 Correct 13 ms 23828 KB Output is correct
14 Correct 16 ms 23960 KB Output is correct
15 Correct 14 ms 23948 KB Output is correct
16 Correct 13 ms 23824 KB Output is correct
17 Correct 13 ms 23828 KB Output is correct
18 Correct 13 ms 23816 KB Output is correct
19 Correct 13 ms 23828 KB Output is correct
20 Correct 14 ms 23828 KB Output is correct
21 Correct 13 ms 23816 KB Output is correct
22 Correct 12 ms 23892 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 23856 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 13 ms 23764 KB Output is correct
5 Correct 15 ms 23764 KB Output is correct
6 Correct 12 ms 23832 KB Output is correct
7 Correct 13 ms 23828 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 15 ms 23764 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Correct 373 ms 66896 KB Output is correct
12 Correct 345 ms 62468 KB Output is correct
13 Correct 947 ms 67968 KB Output is correct
14 Correct 409 ms 45908 KB Output is correct
15 Correct 989 ms 68060 KB Output is correct
16 Correct 968 ms 68104 KB Output is correct
17 Correct 12 ms 23840 KB Output is correct
18 Correct 12 ms 23832 KB Output is correct
19 Correct 13 ms 23828 KB Output is correct
20 Correct 16 ms 23960 KB Output is correct
21 Correct 14 ms 23948 KB Output is correct
22 Correct 13 ms 23824 KB Output is correct
23 Correct 13 ms 23828 KB Output is correct
24 Correct 13 ms 23816 KB Output is correct
25 Correct 13 ms 23828 KB Output is correct
26 Correct 14 ms 23828 KB Output is correct
27 Correct 13 ms 23816 KB Output is correct
28 Correct 12 ms 23892 KB Output is correct
29 Correct 12 ms 23820 KB Output is correct
30 Correct 399 ms 80200 KB Output is correct
31 Correct 397 ms 80296 KB Output is correct
32 Correct 551 ms 229072 KB Output is correct
33 Correct 490 ms 221164 KB Output is correct
34 Correct 974 ms 81164 KB Output is correct
35 Correct 959 ms 81272 KB Output is correct
36 Correct 985 ms 95992 KB Output is correct
37 Correct 1037 ms 95872 KB Output is correct
38 Correct 778 ms 98828 KB Output is correct
39 Correct 766 ms 98896 KB Output is correct
40 Correct 828 ms 98832 KB Output is correct