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Submission #443808

# Submission time Handle Problem Language Result Execution time Memory
443808 2021-07-12T06:42:16 Z wind_reaper Pipes (BOI13_pipes) C++17
100 / 100
 504 ms 52392 KB 
#include <bits/stdc++.h>

using namespace std;

const int MXN = 100000;

set<array<int, 2>> g[MXN];
int change[MXN], suf[MXN];
bitset<MXN> vis;
int a[MXN], b[MXN], ans[MXN + 1];

void solve(){
	int N, M;
	cin >> N >> M;

	for(int i = 0; i < N; i++)
		cin >> change[i];

	for(int i = 0; i < M; i++){
		int u, v;
		cin >> u >> v;
		--u, --v;
		g[u].insert({v, i});
		g[v].insert({u, i});
	}

	if(M > N){
		cout << 0 << '\n';
		return;
	}

	queue<array<int, 3>> q;
	for(int i = 0; i < N; i++)
		if(g[i].size() < 2){
			q.push({i, (*g[i].begin())[0], (*g[i].begin())[1]});
			vis[i] = 1;
		}

	int cnt = 0;

	while(!q.empty()){
		auto [u, par, idx] = q.front();
		q.pop();

		++cnt;

		int t = change[u];
		ans[idx] += 2*t;
		change[u] -= t;
		change[par] -= t;

		g[par].erase({u, idx});

		if(g[par].size() < 2 && !vis[par]){
			q.push({par, (*g[par].begin())[0], (*g[par].begin())[1]});
			vis[par] = 1;
		}
	}

	if(cnt < N){
		if(!((N - cnt) & 1)){
			cout << 0 << '\n';
			return;
		}

		int x;
		for(int i = 0; i < N; i++) 
			if(!vis[i]) 
				x = i;

		int u = x;
		N = 0;

		while(u != x || N == 0){
			auto [v, idx] = (N == 0 || (*g[u].begin())[0] != a[N-1] ? *g[u].begin() : *g[u].rbegin());
			a[N] = u;
			b[N++] = idx;
			u = v;
		}

		suf[N-1] = change[a[N-1]];
		for(int i = N - 2; i >= 0; --i)
			suf[i] = change[a[i]] - suf[i+1];
		int pre = 0;

		for(int i = 0; i < N; i++){
			pre = change[a[i]] - pre;
			ans[b[i]] = (pre + (i + 1 < N ? suf[i+1] : 0));
		}
	}

	for(int i = 0; i < M; i++)
		cout << ans[i] << '\n';
}

int32_t main(){
	ios_base::sync_with_stdio(false); 
	cin.tie(NULL); 

	solve();

	return 0; 
}

Compilation message

pipes.cpp: In function 'void solve()':
pipes.cpp:74:16: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   74 |   while(u != x || N == 0){
      |         ~~~~~~~^~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 4 ms 4940 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 134 ms 16132 KB Output is correct
5 Correct 3 ms 4940 KB Output is correct
6 Correct 3 ms 4940 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 4940 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 4 ms 5128 KB Output is correct
11 Correct 4 ms 5048 KB Output is correct
12 Correct 4 ms 5068 KB Output is correct
13 Correct 98 ms 13980 KB Output is correct
14 Correct 108 ms 15568 KB Output is correct
15 Correct 118 ms 16164 KB Output is correct
16 Correct 99 ms 14520 KB Output is correct
17 Correct 118 ms 16184 KB Output is correct
18 Correct 127 ms 16196 KB Output is correct
19 Correct 106 ms 15740 KB Output is correct
20 Correct 3 ms 4940 KB Output is correct
21 Correct 4 ms 5068 KB Output is correct
22 Correct 120 ms 16152 KB Output is correct
23 Correct 93 ms 13896 KB Output is correct
24 Correct 118 ms 16208 KB Output is correct
25 Correct 95 ms 14276 KB Output is correct

Subtask #2
70.0 / 70.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4940 KB Output is correct
2 Correct 4 ms 5068 KB Output is correct
3 Correct 91 ms 14856 KB Output is correct
4 Correct 74 ms 14804 KB Output is correct
5 Correct 73 ms 14616 KB Output is correct
6 Correct 497 ms 52320 KB Output is correct
7 Correct 3 ms 4940 KB Output is correct
8 Correct 3 ms 4940 KB Output is correct
9 Correct 3 ms 4940 KB Output is correct
10 Correct 3 ms 4940 KB Output is correct
11 Correct 4 ms 4940 KB Output is correct
12 Correct 3 ms 4940 KB Output is correct
13 Correct 3 ms 4940 KB Output is correct
14 Correct 3 ms 4940 KB Output is correct
15 Correct 4 ms 5068 KB Output is correct
16 Correct 4 ms 5068 KB Output is correct
17 Correct 4 ms 5068 KB Output is correct
18 Correct 4 ms 5068 KB Output is correct
19 Correct 4 ms 5068 KB Output is correct
20 Correct 4 ms 5068 KB Output is correct
21 Correct 4 ms 5196 KB Output is correct
22 Correct 4 ms 5068 KB Output is correct
23 Correct 83 ms 14400 KB Output is correct
24 Correct 107 ms 16484 KB Output is correct
25 Correct 87 ms 14884 KB Output is correct
26 Correct 70 ms 14760 KB Output is correct
27 Correct 68 ms 14672 KB Output is correct
28 Correct 80 ms 15172 KB Output is correct
29 Correct 386 ms 42980 KB Output is correct
30 Correct 112 ms 16080 KB Output is correct
31 Correct 110 ms 16728 KB Output is correct
32 Correct 112 ms 16312 KB Output is correct
33 Correct 94 ms 15540 KB Output is correct
34 Correct 73 ms 14688 KB Output is correct
35 Correct 79 ms 14768 KB Output is correct
36 Correct 80 ms 14800 KB Output is correct
37 Correct 501 ms 52392 KB Output is correct
38 Correct 102 ms 16324 KB Output is correct
39 Correct 118 ms 16196 KB Output is correct
40 Correct 115 ms 16476 KB Output is correct
41 Correct 77 ms 15240 KB Output is correct
42 Correct 86 ms 14676 KB Output is correct
43 Correct 69 ms 14680 KB Output is correct
44 Correct 86 ms 14424 KB Output is correct
45 Correct 504 ms 46776 KB Output is correct
46 Correct 97 ms 16068 KB Output is correct
47 Correct 108 ms 16452 KB Output is correct
48 Correct 104 ms 16708 KB Output is correct
49 Correct 109 ms 15016 KB Output is correct
50 Correct 74 ms 14696 KB Output is correct
51 Correct 74 ms 14716 KB Output is correct
52 Correct 72 ms 14544 KB Output is correct
53 Correct 497 ms 47936 KB Output is correct
54 Correct 108 ms 16076 KB Output is correct