Submission #230454

#	Time	Username	Problem	Language	Result	Execution time	Memory
230454		BamiTorabi	Pipes (BOI13_pipes)	C++14	100 / 100	505 ms	56416 KiB

pipes

//Sasayego! Sasayego! Shinzou wo Sasageyo!

#include <iostream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <ctime>
#include <cstring>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <numeric>
#include <bitset>
#include <ctime>
#define debug(x)  cerr << #x << " = " << x << endl
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <ll, ll> pll;
typedef pair <int, int> pii;

const int maxN = 1e5 + 5;
const int maxM = 5e5 + 5;
const ll INF = 1e18;
const ll MOD = 1e9 + 7;

bool mark[maxN];
int c[maxN];
set <int> G[maxN];
vector <int> vec;
vector <pii> E;
map <pii, int> mp;
queue <int> Q;

pii sorted(int u, int v){
	pii pp = {u, v};
	if (pp.first > pp.second)
		swap(pp.first, pp.second);
	return pp;
}

int main(){
	time_t START = clock();
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int n, m; scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++){
		scanf("%d", c + i);
		c[i] *= 2;
	}
	for (int i = 0; i < m; i++){
		int u, v; scanf("%d%d", &u, &v);
		tie(u, v) = sorted(u, v);
		G[u].insert(v);
		G[v].insert(u);
		E.push_back({u, v});
	}
	if (m > n)
		return printf("0\n"), 0;
	for (int i = 1; i <= n; i++)
		if ((int)G[i].size() == 1)
			Q.push(i);
	while (!Q.empty()){
		int v = Q.front();
		Q.pop();
		if ((int)G[v].size() != 1)
			continue;
		int u = *G[v].begin();
		G[v].clear();
		mp[sorted(u, v)] = c[v];
		c[u] -= c[v];
		G[u].erase(G[u].lower_bound(v));
		if ((int)G[u].size() == 1)
			Q.push(u);
	}
	int cnt = 0;
	for (int i = 1; i <= n; i++)
		cnt += ((int)G[i].size() == 2);
	if (cnt > 0 && cnt % 2 == 0)
		return printf("0\n"), 0;
	if (cnt)
		for (int i = 1; i <= n; i++)
			if ((int)G[i].size() == 2){
				vec.push_back(i);
				int u = *(G[i].begin());
				G[i].erase(G[i].begin());
				int x = *(G[i].begin());
				G[x].erase(G[x].lower_bound(i));
				ll ans = c[i];
				while (x != i){
					vec.push_back(x);
					ans = c[x] - ans;
					int y = *(G[x].begin());
					G[x].erase(G[x].begin());
					if (y != i)	
						G[y].erase(G[y].lower_bound(x));
					x = y;
				}
				c[u] -= ans / 2;
				c[i] -= ans / 2;
				mp[sorted(i, u)] = ans / 2;
				break;
			}
	for (int i = 1; i < (int)vec.size(); i++){
		mp[sorted(vec[i - 1], vec[i])] = c[vec[i - 1]];
		c[vec[i]] -= c[vec[i - 1]];
	}
	for (pii e : E)
		printf("%d\n", mp[e]);
	time_t FINISH = clock();
	cerr << "Execution time: " << (ld)(FINISH - START) / CLOCKS_PER_SEC * 1000.0 << " milliseconds.\n";
	return 0;
}
 

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:48:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  int n, m; scanf("%d%d", &n, &m);
            ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:50:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", c + i);
   ~~~~~^~~~~~~~~~~~~
pipes.cpp:54:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int u, v; scanf("%d%d", &u, &v);
             ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 70 / 70