Submission #144993

#	Time	Username	Problem	Language	Result	Execution time	Memory
144993		cheetose	전압 (JOI14_voltage)	C++11	100 / 100	175 ms	18780 KiB

voltage

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<vector>
#include<queue>
#include<bitset>
#include<string>
#include<stack>
#include<set>
#include<unordered_set>
#include<map>
#include<unordered_map>
#include<cstring>
#include<complex>
#include<cmath>
#include<iomanip>
#include<numeric>
#include<algorithm>
#include<list>
#include<functional>
#include<cassert>
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define y0 y12
#define y1 y22
#define INF 987654321
#define PI 3.141592653589793238462643383279502884
#define fup(i,a,b,c) for(int (i)=(a);(i)<=(b);(i)+=(c))
#define fdn(i,a,b,c) for(int (i)=(a);(i)>=(b);(i)-=(c))
#define MEM0(a) memset((a),0,sizeof(a));
#define MEM_1(a) memset((a),-1,sizeof(a));
#define ALL(a) a.begin(),a.end()
#define SYNC ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll> Pll;
typedef pair<ld, ld> Pd;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<double> Vd;
typedef vector<Pi> VPi;
typedef vector<Pll> VPll;
typedef vector<Pd> VPd;
typedef tuple<int, int, int> iii;
typedef tuple<int,int,int,int> iiii;
typedef tuple<ll, ll, ll> LLL;
typedef vector<iii> Viii;
typedef vector<LLL> VLLL;
typedef complex<double> base;
const ll MOD = 1000000007;
ll POW(ll a, ll b, ll MMM = MOD) {ll ret=1; for(;b;b>>=1,a=(a*a)%MMM)if(b&1)ret=(ret*a)% MMM; return ret; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a*(b / gcd(a, b)); }
int dx[] = { 0,1,0,-1,1,1,-1,-1 }, dy[] = { 1,0,-1,0,1,-1,1,-1 };

int n,m,k;
VPi v[100001];
int ee[200001],ev[100001],oe[200001],ov[100001];
int depth[100001],num[100001],c;
void dfs(int N,int p, int d)
{
	num[N]=++c;
	depth[N]=d;
	for(auto P:v[N])
	{
		if(P.Y==p || num[P.X]>num[N])continue;
		if(num[P.X])
		{
			if((depth[N]-depth[P.X]) &1)
			{
				ee[P.Y]++;
				ev[N]++,ev[P.X]--;
			}
			else
			{
				oe[P.Y]++;
				ov[N]++,ov[P.X]--,k++;
			}
		}
		else
		{
			dfs(P.X,P.Y,d+1);
			ov[N]+=ov[P.X];
			ev[N]+=ev[P.X];
		}
	}
	oe[p]+=ov[N],ee[p]+=ev[N];
}
int main() {
	scanf("%d%d",&n,&m);
	fup(i,1,m,1)
	{
		int x,y;
		scanf("%d%d",&x,&y);
		v[x].pb(mp(y,i));
		v[y].pb(mp(x,i));
	}
	fup(i,1,n,1)if(!num[i])dfs(i,0,1);
	int ans=0;
	fup(i,1,m,1)if(oe[i]==k && ee[i]==0)ans++;
	printf("%d",ans);
}

Compilation message (stderr)

voltage.cpp: In function 'int main()':
voltage.cpp:97:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~
voltage.cpp:101:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&x,&y);
   ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 35 / 35
• Subtask 4: 45 / 45