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Submission #1092423

# Submission time Handle Problem Language Result Execution time Memory
1092423 2024-09-24T03:52:25 Z MinhTuan11 Firefighting (NOI20_firefighting) C++17
74 / 100
 301 ms 69120 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) {
	// cout << u << '\n';
	vector<int> a;
	int mini = inf;
	for(pii w : adj[u]) {
		int v = w.fi, c = w.se;
		if(c > mid) continue;
		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(u == 1 || h[u] > mid) {
		// cout << u << ' ' << a.back() << ' ' << mini << '\n';
		if(mini > mid) {
			// cout << "+ " << u << '\n';
			pos.push_back(u);
			cnt++;
			return;
		}
		else {
			if(a.size() == 0) return;
			if(a.back() + mini > mid) {
				// cout << "+ " << u << '\n';
				pos.push_back(u);
				cnt++;
				return;
			}
		}
		return;
	}
	if(a.size() == 0) {
		if(h[u] > mid) {
			// cout << "+ " << u << '\n';
			assert(1 == 2);
			pos.push_back(u);
			cnt++;
			g[u] = 0;
			b[u] = -h[u];
		}
		else {
			g[u] = inf;
			b[u] = 0;
		}
		return;
	}
	// if(h[u] > mid) {
		// if(mini > mid) {
			// pos.push_back(u);
			// cnt++;
			// g[u] = 0;
			// b[u] = -h[u];
		// }
		// else {
			// g[u] = mini;
			// b[u] = 0;
		// }
		// return;
	// }
	// if(a[0] > mid) {
		// cout << u << '\n';
		// //assert(1 == 2);
		// // 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);
    for(int i = 1; i <= n; i++) {
    	int pcnt = cnt;
    	if(i == 1 || h[i] > mid) {
    		dfs(i, 0);
    		// if(cnt == pcnt) {
    			// cnt++;
    			// pos.push_back(i);
    		// }
    	}
    }
    // 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:196:10: warning: unused variable 'pcnt' [-Wunused-variable]
  196 |      int pcnt = cnt;
      |          ^~~~
Firefighting.cpp:178:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  178 |      freopen("file.inp", "r", stdin);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Firefighting.cpp:179:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  179 |      freopen("file.out", "w", stdout);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 200 ms 45376 KB Output is correct
2 Correct 211 ms 45632 KB Output is correct
3 Correct 60 ms 20552 KB Output is correct
4 Correct 186 ms 44616 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 3 ms 7520 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 4 ms 7516 KB Output is correct
3 Correct 3 ms 7516 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 7532 KB Output is correct
8 Correct 3 ms 7516 KB Output is correct
9 Correct 3 ms 7516 KB Output is correct
10 Correct 3 ms 7516 KB Output is correct
11 Correct 3 ms 7492 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

Subtask #3
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7516 KB Output is correct
2 Correct 4 ms 7516 KB Output is correct
3 Correct 3 ms 7516 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 7516 KB Output is correct
8 Correct 3 ms 7516 KB Output is correct
9 Correct 3 ms 7516 KB Output is correct
10 Correct 3 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 7336 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 7516 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 7572 KB Output is correct
22 Correct 3 ms 7516 KB Output is correct
23 Correct 3 ms 7516 KB Output is correct
24 Correct 3 ms 7512 KB Output is correct
25 Correct 3 ms 7516 KB Output is correct
26 Correct 3 ms 7516 KB Output is correct

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 206 ms 45480 KB Output is correct
2 Correct 115 ms 27392 KB Output is correct
3 Correct 115 ms 27972 KB Output is correct
4 Correct 95 ms 25416 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 3 ms 7516 KB Output is correct
7 Correct 214 ms 44364 KB Output is correct
8 Correct 191 ms 43960 KB Output is correct
9 Correct 211 ms 43836 KB Output is correct
10 Correct 205 ms 43904 KB Output is correct
11 Correct 192 ms 45640 KB Output is correct
12 Correct 130 ms 33092 KB Output is correct
13 Correct 82 ms 23112 KB Output is correct
14 Correct 119 ms 30036 KB Output is correct
15 Correct 164 ms 36416 KB Output is correct
16 Correct 184 ms 38220 KB Output is correct
17 Correct 145 ms 34000 KB Output is correct
18 Correct 165 ms 33600 KB Output is correct

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 260 ms 39900 KB Output is correct
2 Correct 247 ms 37204 KB Output is correct
3 Correct 230 ms 39508 KB Output is correct
4 Correct 80 ms 22236 KB Output is correct
5 Correct 275 ms 61508 KB Output is correct
6 Correct 265 ms 59060 KB Output is correct
7 Correct 281 ms 65500 KB Output is correct
8 Correct 278 ms 63920 KB Output is correct
9 Correct 266 ms 53444 KB Output is correct
10 Correct 283 ms 51656 KB Output is correct
11 Correct 296 ms 69120 KB Output is correct
12 Correct 135 ms 29632 KB Output is correct
13 Correct 301 ms 57568 KB Output is correct
14 Correct 263 ms 49736 KB Output is correct
15 Correct 234 ms 40396 KB Output is correct
16 Correct 194 ms 37972 KB Output is correct
17 Correct 209 ms 37660 KB Output is correct
18 Correct 217 ms 39764 KB Output is correct
19 Correct 127 ms 30032 KB Output is correct
20 Correct 66 ms 20172 KB Output is correct
21 Correct 214 ms 39692 KB Output is correct