POJ 3678
题目大意
暂无
题目解法
暂无
RTFC
#include <cstdio>
#include <cstring>
inline int min(int a, int b) { return a < b ? a : b; }
const int maxn = 10010, maxm = 4000010;
int head[maxn], next[maxm], to[maxm], ecnt;
inline void addEdge(int f, int t)
{
next[ecnt] = head[f];
head[f] = ecnt;
to[ecnt] = t;
ecnt++;
}
int dfn[maxn], low[maxn], stk[maxn], scc[maxn], top, idx, scccnt;
void tarjan(int x)
{
dfn[x] = low[x] = ++idx;
stk[top++] = x;
for (int i = head[x]; ~i; i = next[i])
if (!dfn[to[i]])
tarjan(to[i]), low[x] = min(low[x], low[to[i]]);
else if (!scc[to[i]])
low[x] = min(low[x], dfn[to[i]]);
if (dfn[x] == low[x])
{
scccnt++;
do
scc[stk[--top]] = scccnt;
while (stk[top] != x);
}
}
int main()
{
int n, m;
while (~scanf("%d%d", &n, &m))
{
memset(dfn, 0, sizeof(dfn));
memset(low, 0, sizeof(low));
memset(scc, 0, sizeof(scc));
memset(head, -1, sizeof(head));
ecnt = top = idx = scccnt = 0;
for (int i = 0, u, v, w; i < m; ++i)
{
char op[5];
scanf("%d%d%d%s", &u, &v, &w, op);
if (op[0] == 'A')
if (w)
{
addEdge(u << 1, v << 1 | 1), addEdge(v << 1, u << 1 | 1);
addEdge(u << 1, v << 1), addEdge(v << 1 | 1, u << 1 | 1);
addEdge(u << 1 | 1, v << 1 | 1), addEdge(v << 1, u << 1);
}
else
{
addEdge(u << 1 | 1, v << 1), addEdge(v << 1 | 1, u << 1);
}
if (op[0] == 'O')
if (w)
{
addEdge(u << 1, v << 1 | 1), addEdge(v << 1, u << 1 | 1);
}
else
{
addEdge(u << 1, v << 1), addEdge(v << 1 | 1, u << 1 | 1);
addEdge(u << 1 | 1, v << 1 | 1), addEdge(v << 1, u << 1);
addEdge(u << 1 | 1, v << 1), addEdge(v << 1 | 1, u << 1);
}
if (op[0] == 'X')
if (w)
{
addEdge(u << 1, v << 1 | 1), addEdge(v << 1, u << 1 | 1);
addEdge(u << 1 | 1, v << 1), addEdge(v << 1 | 1, u << 1);
}
else
{
addEdge(u << 1, v << 1), addEdge(v << 1 | 1, u << 1 | 1);
addEdge(u << 1 | 1, v << 1 | 1), addEdge(v << 1, u << 1);
}
}
for (int i = 0; i < (n << 1); i++)
if (!dfn[i]) tarjan(i);
bool flag = true;
for (int i = 0; i < n && flag; i++)
if (scc[i << 1] == scc[i << 1 | 1])
flag = false;
puts(flag ? "YES" : "NO");
}
return 0;
}