sysy-data/hidden_functional_c/sy/09_BFS.sy

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#include "sylib.h"
int quick_read(){
int ch = getch(); int x = 0, f = 0;
while (ch < 48 || ch > 57){
if (ch == 45) f = 1;
ch = getch();
}
while (ch >= 48 && ch <=57){
x = x * 10 + ch - 48;
ch = getch();
}
if (f) return -x;
else return x;
}
int n, m;
#define maxn 1005
#define maxm 5005
int to[maxm], next[maxm], head[maxn], cnt = 0;
int que[maxn], h, tail, inq[maxn];
void add_edge(int from, int To){
to[cnt] = To;
next[cnt] = head[from];
head[from] = cnt;
cnt = cnt + 1;
to[cnt] = from;
next[cnt] = head[To];
head[To] = cnt;
cnt = cnt + 1;
}
void init(){
int i = 0;
while (i < maxn){
head[i] = -1;
i = i + 1;
}
}
void inqueue(int x){
inq[x] = 1;
tail = tail + 1;
que[tail] = x;
}
int pop_queue(){
h = h + 1;
int res = que[h];
return que[h];
}
int same(int s, int t){
h = 0;
tail = 0;
inqueue(s);
int res = 0;
while (h < tail){
int x = pop_queue();
if (x == t) res = 1;
int i = head[x];
while (i != -1){
if (!inq[to[i]]) inqueue(to[i]);
i = next[i];
}
}
int i = 0;
while (i <= tail){
inq[que[i]] = 0;
i = i + 1;
}
return res;
}
int main(){
n = quick_read(); m = quick_read();
init();
while (m){
int ch = getch();
while (ch != 81 && ch != 85){
ch = getch();
}
if (ch == 81){ // query
int x = quick_read(), y = quick_read();
putint(same(x, y));
putch(10);
}else{ // union
int x = quick_read(), y = quick_read();
add_edge(x, y);
}
m = m - 1;
}
return 0;
}