OJ-Problems-Source/HDOJ/1824_autoAC.cpp

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#include <cstdio>
#include <vector>
#include <cstring>
#include <iostream>
using namespace std;
const int MAX_N = 2 * 5000 + 10;
struct TwoSAT {
int n;
vector<int> G[2 * MAX_N];
bool mark[2 * MAX_N];
int S[2 * MAX_N], c;
void Init(int n)
{
this->n = n;
for (int i = 0; i <= 2 * n; ++i)
G[i].clear();
memset(mark, 0, sizeof(mark));
}
bool Dfs(int x)
{
if (mark[x ^ 1]) return false;
if (mark[x]) return true;
mark[x] = true;
S[c++] = x;
for (int i = 0; i < G[x].size(); ++i)
{
if (!Dfs(G[x][i]))
return false;
}
return true;
}
void AddClause(int x, int y)
{
int a = 2 * x;
int b = 2 * y;
G[a ^ 1].push_back(b);
G[b ^ 1].push_back(a);
}
void AddClauseTeam(int i, int j, int k)
{
int a = 2 * i;
int b = 2 * j;
int c = 2 * k;
G[a].push_back(b ^ 1);
G[a].push_back(c ^ 1);
G[b].push_back(a ^ 1);
G[b].push_back(c);
G[c].push_back(a ^ 1);
G[c].push_back(b);
G[a ^ 1].push_back(b);
G[a ^ 1].push_back(c);
G[b ^ 1].push_back(a);
G[b ^ 1].push_back(c ^ 1);
G[c ^ 1].push_back(a);
G[c ^ 1].push_back(b ^ 1);
}
bool Solve()
{
for (int i = 0; i < 2 * n; i += 2)
{
if (!mark[i] && !mark[i + 1])
{
c = 0;
if (!Dfs(i))
{
while (c > 0) mark[S[--c]] = false;
if (!Dfs(i + 1))
return false;
}
}
}
return true;
}
};
TwoSAT sat;
int main()
{
int n, m;
while (scanf("%d %d", &n, &m) != EOF)
{
int a, b, c;
sat.Init(3 * n);
for (int i = 0; i < n; ++i)
{
scanf("%d %d %d", &a, &b, &c);
sat.AddClauseTeam(a, b, c);
}
for (int i = 0; i < m; ++i)
{
scanf("%d %d", &a, &b);
sat.AddClause(a, b);
}
bool ok = sat.Solve();
if (ok)
printf("yes\n");
else
printf("no\n");
}
return 0;
}