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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXN 1000
#define MAX_HASH 1021
typedef struct Edge Edge;
typedef struct Set Set;
typedef Set *Set_t;
typedef struct SetNode {
int val;
struct SetNode *next;
} SetNode;
struct Set {
SetNode *head[MAX_HASH];
};
Set_t set_create() {
Set_t set = (Set_t)malloc(sizeof(Set));
memset(set->head, 0, sizeof set->head);
return set;
}
int set_belongs(Set_t set, int val) {
SetNode *p;
for (p = set->head[val % MAX_HASH]; p; p = p->next)
if (p->val == val) return 1;
return 0;
}
void set_push(Set_t set, int val) {
SetNode *p = (SetNode*)malloc(sizeof(SetNode));
int hv = val % MAX_HASH;
p->next = set->head[hv];
p->val = val;
set->head[hv] = p;
}
struct Edge {
int to;
Edge *next;
} *head[MAXN], *rhead[MAXN];
typedef struct DFNode DFNode;
struct DFNode {
int id;
DFNode *next;
};
void add_edge(int a, int b, Edge **head) {
Edge *p = (Edge*)malloc(sizeof(Edge));
p->to = b;
p->next = head[a];
head[a] = p;
}
int dom[MAXN], ord[MAXN], vis[MAXN], par[MAXN];
int n, n0, m;
DFNode *df[MAXN];
Set_t dfset[MAXN];
void dfs(int u, int v) {
static int ocnt = 0;
Edge *e;
if (vis[u] != -1) return;
par[u] = v;
vis[u] = 0;
for (e = head[u]; e; e = e->next)
dfs(e->to, u);
vis[u] = ocnt;
ord[ocnt++] = u;
}
int intersect(int b1, int b2) {
while (b1 != b2)
if (b1 < b2) b1 = dom[b1];
else b2 = dom[b2];
return b1;
}
int main() {
int i;
int ch = 1;
scanf("%d %d %d", &n, &m, &n0);
for (i = 0; i < m; i++)
{
int a, b;
scanf("%d %d", &a, &b);
add_edge(a, b, head);
add_edge(b, a, rhead);
}
for (i = 0; i < n; i++)
vis[i] = dom[i] = -1;
dfs(n0, -1);
for (i = 0; i < n; i++)
printf("%d ", ord[i]); puts("");
dom[vis[n0]] = vis[n0];
while (ch)
{
int i;
ch = 0;
for (i = n - 2; i >= 0; i--)
{
int id = ord[i];
Edge *e = rhead[id];
int new_idom = vis[par[id]];
for (; e; e = e->next)
{
int p = e->to;
if (vis[p] == new_idom) continue;
if (dom[vis[p]] != -1)
new_idom = intersect(vis[p], new_idom);
}
if (dom[i] != new_idom)
{
ch = 1;
dom[i] = new_idom;
}
}
for (i = 0; i < n; i++)
printf("%d ", ord[dom[vis[i]]]); puts("");
}
for (i = 0; i < n; i++)
{
dfset[i] = set_create();
df[i] = NULL;
}
for (i = 0; i < n; i++)
if (rhead[i] && rhead[i]->next)
{
Edge *p = rhead[i];
for (; p; p = p->next)
{
int runner = p->to;
while (vis[runner] != dom[vis[i]])
{
if (!set_belongs(dfset[runner], i))
{
DFNode *np = (DFNode*)malloc(sizeof(DFNode));
np->id = i;
np->next = df[runner];
set_push(dfset[runner], i);
df[runner] = np;
}
runner = ord[dom[vis[runner]]];
}
}
}
for (i = 0; i < n; i++)
{
DFNode *p = df[i];
printf("%d: ", i);
for (; p; p = p->next)
printf("%d ", p->id); puts("");
}
return 0;
}
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