POJ 1236
题目大意
暂无
题目解法
暂无
RTFC
#include <cstdio>
inline int min(int a, int b) { return a < b ? a : b; }
const int maxn = 110, maxm = 10100;
int head[maxn], next[maxm], to[maxm], ecnt, f[maxn], g[maxn];
inline void addEdge(int f, int t)
{
ecnt++;
next[ecnt] = head[f];
head[f] = ecnt;
to[ecnt] = t;
}
int dfn[maxn], low[maxn], stk[maxn], scc[maxn], scccnt, top, idx;
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;
scanf("%d", &n);
for (int i = 1, x; i <= n; i++)
for (scanf("%d", &x); x; scanf("%d", &x))
addEdge(i, x);
for (int i = 1; i <= n; i++)
if (!dfn[i]) tarjan(i);
for (int i = 1; i <= n; i++)
for (int j = head[i]; j; j = next[j])
if (scc[i] != scc[to[j]])
f[scc[i]]++, g[scc[to[j]]]++;
int ans1 = 0, ans2 = 0;
if (scccnt == 1)
printf("1\n0");
else
{
for (int i = 1; i <= scccnt; i++)
ans1 += f[i] == 0, ans2 += g[i] == 0;
printf("%d\n%d", ans2, ans1 > ans2 ? ans1 : ans2);
}
return 0;
}