oj.uz

답안 #16496

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
16496 2015-08-26T14:41:46 Z gs14004 전압 (JOI14_voltage) C++14
100 / 100
 203 ms 24956 KB 
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
typedef pair<int,int> pi;

vector<pi> graph[100005];
vector<pi> odd_cyc, backedg;

int n, m;
int par[100005][17], dep[100005], low[100005], dfn[100005], piv;

bool vis[100005];
bool vise[200005];

int cutedge;
int gap[100005];

void dfs(int x){
	low[x] = dfn[x] = ++piv;
	for(int i=1; i<=16; i++){
		par[x][i] = par[par[x][i-1]][i-1];
	}
	for(auto &i : graph[x]){
		if(!vis[i.second]){
			vise[i.first] = 1;
			vis[i.second] = 1;
			dep[i.second] = dep[x] + 1;
			par[i.second][0] = x;
			dfs(i.second);
			low[x] = min(low[x], low[i.second]);
		}
		else{
			if(vise[i.first]) continue;
			vise[i.first] = 1;
			low[x] = min(low[x], dfn[i.second]);
			if((dep[x] - dep[i.second]) % 2 == 0){
				odd_cyc.push_back(pi(i.second, x));
			}
			else backedg.push_back(pi(i.second, x));
		}
	}
	if(par[x][0] && low[x] == dfn[x]){
		cutedge++;
	}
}

int lca(int s, int e){
	if(dep[s] > dep[e]) swap(s,e);
	int dx = dep[e] - dep[s];
	for(int i=0; i<17; i++){
		if((dx >> i) & 1) e = par[e][i];
	}
	for(int i=16; i>=0; i--){
		if(par[s][i] != par[e][i]){
			s = par[s][i];
			e = par[e][i];
		}
	}
	if(s != e) return par[s][0];
	return s;
}

bool vis2[100005];
int dx[100005];
int cnts;

void fill(int x){
	for(auto &i : graph[x]){
		if(!vis2[i.second]){
			vis2[i.second] = 1;
			fill(i.second);
			dx[x] += dx[i.second];
		}
	}
	if(par[x][0] && dx[x] == odd_cyc.size()){
		cnts++;
	}
}

int solve(int x){
	cnts = 0;
	for(auto &i : odd_cyc){
		dx[i.first]++;
		dx[i.second]++;
		dx[lca(i.first, i.second)]-=2;
	}
	for(auto &i : backedg){
		dx[i.first]--;
		dx[i.second]--;
		dx[lca(i.first, i.second)]+=2;
	}
	vis2[x] = 1;
	fill(x);
	return cnts;
}

int main(){
	scanf("%d %d",&n,&m);
	for(int i=0; i<m; i++){
		int s, e;
		scanf("%d %d",&s,&e);
		graph[s].push_back(pi(i, e));
		graph[e].push_back(pi(i, s));
	}
	int bad = 0, cnt = 0;
	for(int i=1; i<=n; i++){
		if(!vis[i]){
			vis[i] = 1;
			odd_cyc.clear();
			backedg.clear();
			cutedge = 0;
			dfs(i);
			if(odd_cyc.empty()){
				if(!bad) cnt += cutedge;
			}
			else{
				if(bad){
					puts("0");
					return 0;
				}
				bad = 1;
				cnt = solve(i) + (odd_cyc.size() == 1);
			}
		}
	}
	printf("%d",cnt);
}

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 12544 KB Output is correct
2 Correct 0 ms 12544 KB Output is correct
3 Correct 0 ms 12544 KB Output is correct
4 Correct 0 ms 12544 KB Output is correct
5 Correct 3 ms 12544 KB Output is correct
6 Correct 2 ms 12544 KB Output is correct
7 Correct 0 ms 12544 KB Output is correct
8 Correct 0 ms 12544 KB Output is correct
9 Correct 0 ms 12544 KB Output is correct
10 Correct 5 ms 12544 KB Output is correct
11 Correct 0 ms 12544 KB Output is correct
12 Correct 0 ms 12544 KB Output is correct

Subtask #2
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 62 ms 16608 KB Output is correct
2 Correct 64 ms 19064 KB Output is correct
3 Correct 47 ms 16608 KB Output is correct
4 Correct 107 ms 20356 KB Output is correct
5 Correct 7 ms 13024 KB Output is correct
6 Correct 64 ms 18004 KB Output is correct
7 Correct 89 ms 21708 KB Output is correct
8 Correct 80 ms 21704 KB Output is correct

Subtask #3
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 42 ms 16608 KB Output is correct
2 Correct 38 ms 21700 KB Output is correct
3 Correct 64 ms 21704 KB Output is correct
4 Correct 0 ms 12544 KB Output is correct
5 Correct 64 ms 18300 KB Output is correct
6 Correct 55 ms 16240 KB Output is correct
7 Correct 67 ms 18804 KB Output is correct
8 Correct 86 ms 19640 KB Output is correct
9 Correct 96 ms 19876 KB Output is correct
10 Correct 79 ms 18532 KB Output is correct
11 Correct 78 ms 16240 KB Output is correct
12 Correct 67 ms 17452 KB Output is correct

Subtask #4
45.0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 76 ms 19772 KB Output is correct
2 Correct 83 ms 24956 KB Output is correct
3 Correct 7 ms 12544 KB Output is correct
4 Correct 74 ms 19852 KB Output is correct
5 Correct 98 ms 20872 KB Output is correct
6 Correct 108 ms 19680 KB Output is correct
7 Correct 149 ms 22928 KB Output is correct
8 Correct 176 ms 23280 KB Output is correct
9 Correct 177 ms 21708 KB Output is correct
10 Correct 104 ms 24176 KB Output is correct
11 Correct 177 ms 21820 KB Output is correct
12 Correct 203 ms 24232 KB Output is correct
13 Correct 146 ms 21240 KB Output is correct
14 Correct 188 ms 24524 KB Output is correct
15 Correct 168 ms 24780 KB Output is correct
16 Correct 179 ms 23508 KB Output is correct
17 Correct 129 ms 23460 KB Output is correct
18 Correct 191 ms 24672 KB Output is correct