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Submission #1091251

# Submission time Handle Problem Language Result Execution time Memory
1091251 2024-09-20T09:28:55 Z MinhTuan11 Firefighting (NOI20_firefighting) C++17
55 / 100
 324 ms 69332 KB 
#include <bits/stdc++.h>

#define int long long
#define fi first
#define se second

const int N = 3e5 + 5;
const int K = 1e2 + 5;
const int mod = 1e9 + 7;
const int inf = 1e18;

#define all(v) (v).begin(), (v).end()
#define pii pair<int, int> 

using namespace std;

mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());

int n, f, h[N];
vector<pii> adj[N];
vector<int> pos;
int g[N], b[N], l, r, mid, cnt;

void pre(int u, int p) {
	for(pii w : adj[u]) {
		int v = w.fi, c = w.se;
		if(v == p) continue;
		h[v] = c;
		pre(v, u);
	}
}

void dfs(int u, int p) {
	vector<int> a;
	int mini = inf;
	for(pii w : adj[u]) {
		int v = w.fi, c = w.se;
		if(v == p) continue;
		dfs(v, u);
		// cout << v << ' ' << b[v] << '\n';
		a.push_back(b[v] + c);
		mini = min(mini, g[v] + c);
	}
	sort(all(a));
	if(a.size() == 0) {
		if(h[u] > mid) {
			// cout << "+ " << u << '\n';
			pos.push_back(u);
			cnt++;
			g[u] = 0;
			b[u] = -h[u];
		}
		else {
			g[u] = inf;
			b[u] = 0;
		}
		return;
	}
	if(u == 1) {
		// cout << u << ' ' << a.back() << ' ' << mini << '\n';
		if(mini > mid) {
			// cout << "+ " << u << '\n';
			pos.push_back(u);
			cnt++;
			return;
		}
		else {
			if(a.back() + mini > mid) {
				// cout << "+ " << u << '\n';
				pos.push_back(u);
				cnt++;
				return;
			}
		}
	}
	if(a[0] > mid) {
		if(h[u] > mid) {
			// cout << "+ " << u << '\n';
			pos.push_back(u);
			cnt++;
			g[u] = 0;
			b[u] = -h[u];
		}
		else {
			g[u] = inf;
			b[u] = 0;
		}
		return;
	}
	if(mini > mid) {
		// cout << u << ' ' << a.back() << ' ' << mini << '\n';
		if(a.back() + h[u] > mid) {
			// cout << "+ " << u << '\n';
			pos.push_back(u);
			cnt++;
			g[u] = 0;
			b[u] = -h[u];
		}
		else {
			g[u] = mini;
			b[u] = a.back();
		}
	}
	else {
		// cout << u << ' ' << a.back() << ' ' << mini << '\n';
		if(a.back() + h[u] > mid) {
			if(a.back() + mini > mid) {
				// cout << "+ " << u << '\n';
				pos.push_back(u);
				cnt++;
				g[u] = 0;
				b[u] = -h[u];
			}
			else {
				g[u] = mini;
				b[u] = 0;
			}
		}
		else {
			g[u] = mini;
			b[u] = a.back();
			if(a.back() + mini <= mid) b[u] = -h[u];
		}
	}
}

namespace checker {
	bool check() {
		priority_queue<pii, vector<pii>, greater<pii>> q;
		vector<int> d(n + 1, inf);
		for(int x : pos) {
			q.push({0, x});
			d[x] = 0;
		}
		while(q.size()) {
			int y = q.top().se;
			int dy = q.top().fi;
			q.pop();
			if(dy > d[y]) continue;
			if(dy > mid) return 0;
			// cout << y << ' ' << d[y] << '\n';
			for(pii z : adj[y]) {
				if(d[z.fi] > d[y] + z.se) {
					d[z.fi] = d[y] + z.se;
					q.push({d[z.fi], z.fi});
				}
			}
		}
		return 1;
	}
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    if(ifstream("file.inp")){
    	freopen("file.inp", "r", stdin);
    	freopen("file.out", "w", stdout);
    }
    
    cin >> n >> f;
    for(int i = 2; i <= n; i++) {
    	int j, t;
    	int x;
    	cin >> x;
    	cin >> j >> t;
    	adj[x].push_back({j, t});
    	adj[j].push_back({x, t});
    	r += t;
    	// cout << i << ' ' << j << ' ' << t << '\n';
    }
    mid = f;
    pre(1, 0);
    dfs(1, 0);
    // l = 3, r = 3;
    // int res = inf;
    // while(l <= r) {
    	// mid = l + r >> 1;
    	// cnt = 0;
    	// for(int i = 1; i <= n; i++) {
    		// g[i] = inf;
    	// }
    	// dfs(1, 0);
    	// // cout << "cnt: " << cnt << '\n';
    	// if(cnt <= f) {
    		// res = mid;
    		// r = mid - 1;
    	// }
    	// else l = mid + 1;
    // }
    // cout << res << '\n';
    if(cnt == 0) {
    	cnt++;
    	pos.push_back(1);
    }
    if(!checker::check()) {
    	assert(1 == 2);
    }
    cout << cnt << '\n';
    for(int x : pos) cout << x << ' ';
    
    return 0;
}

// tuntun

Compilation message

Firefighting.cpp: In function 'int main()':
Firefighting.cpp:158:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  158 |      freopen("file.inp", "r", stdin);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Firefighting.cpp:159:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  159 |      freopen("file.out", "w", stdout);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 268 ms 50240 KB Output is correct
2 Correct 278 ms 50232 KB Output is correct
3 Correct 79 ms 22340 KB Output is correct
4 Correct 248 ms 49484 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 3 ms 7512 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7516 KB Output is correct
2 Correct 3 ms 7516 KB Output is correct
3 Correct 3 ms 7516 KB Output is correct
4 Correct 6 ms 7516 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 3 ms 7516 KB Output is correct
7 Correct 3 ms 7516 KB Output is correct
8 Correct 5 ms 7288 KB Output is correct
9 Correct 3 ms 7516 KB Output is correct
10 Correct 5 ms 7512 KB Output is correct
11 Correct 3 ms 7516 KB Output is correct
12 Correct 4 ms 7512 KB Output is correct
13 Correct 3 ms 7516 KB Output is correct
14 Correct 3 ms 7516 KB Output is correct
15 Correct 4 ms 7512 KB Output is correct

Subtask #3
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7512 KB Output is correct
2 Correct 4 ms 7516 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7516 KB Output is correct
5 Correct 3 ms 7516 KB Output is correct
6 Correct 3 ms 7516 KB Output is correct
7 Correct 3 ms 7320 KB Output is correct
8 Correct 6 ms 7516 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 5 ms 7516 KB Output is correct
11 Correct 3 ms 7516 KB Output is correct
12 Correct 3 ms 7516 KB Output is correct
13 Correct 3 ms 7516 KB Output is correct
14 Correct 3 ms 7516 KB Output is correct
15 Correct 3 ms 7516 KB Output is correct
16 Correct 3 ms 7516 KB Output is correct
17 Correct 3 ms 7516 KB Output is correct
18 Correct 3 ms 7340 KB Output is correct
19 Correct 3 ms 7516 KB Output is correct
20 Correct 3 ms 7516 KB Output is correct
21 Correct 3 ms 7520 KB Output is correct
22 Correct 3 ms 7516 KB Output is correct
23 Correct 3 ms 7516 KB Output is correct
24 Correct 4 ms 7516 KB Output is correct
25 Correct 3 ms 7516 KB Output is correct
26 Correct 3 ms 7528 KB Output is correct

Subtask #4
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 294 ms 50228 KB Output is correct
2 Correct 117 ms 27468 KB Output is correct
3 Correct 124 ms 28028 KB Output is correct
4 Correct 100 ms 25412 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 3 ms 7516 KB Output is correct
7 Correct 240 ms 44384 KB Output is correct
8 Correct 207 ms 44004 KB Output is correct
9 Correct 215 ms 43956 KB Output is correct
10 Correct 264 ms 43956 KB Output is correct
11 Correct 282 ms 50500 KB Output is correct
12 Incorrect 162 ms 33312 KB Output isn't correct
13 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Incorrect 4 ms 8024 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
38.0 / 38.0

# Verdict Execution time Memory Grader output
1 Correct 304 ms 39696 KB Output is correct
2 Correct 206 ms 37204 KB Output is correct
3 Correct 244 ms 39508 KB Output is correct
4 Correct 85 ms 22140 KB Output is correct
5 Correct 320 ms 61504 KB Output is correct
6 Correct 278 ms 59204 KB Output is correct
7 Correct 286 ms 65520 KB Output is correct
8 Correct 302 ms 64032 KB Output is correct
9 Correct 272 ms 53444 KB Output is correct
10 Correct 288 ms 51848 KB Output is correct
11 Correct 324 ms 69332 KB Output is correct
12 Correct 183 ms 29548 KB Output is correct
13 Correct 323 ms 57524 KB Output is correct
14 Correct 290 ms 49772 KB Output is correct
15 Correct 259 ms 40400 KB Output is correct
16 Correct 215 ms 37804 KB Output is correct
17 Correct 204 ms 37716 KB Output is correct
18 Correct 247 ms 39880 KB Output is correct
19 Correct 126 ms 30040 KB Output is correct
20 Correct 67 ms 20204 KB Output is correct
21 Correct 228 ms 39800 KB Output is correct