PAT a1032题解

#include 
#include 

const int maxn = 100010;

struct Node{
	char data;
	int next;
	bool flag;
}node[maxn];

int main(){
	for(int i = 0; i < maxn; i++){
		node[i].flag = false;
	}
	int s1, s2, n;
	scanf("%d%d%d", &s1, &s2, &n);
	int address, next;
	char data;
	for(int i = 0; i < n; i++){
		scanf("%d %c %d", &address, &data, &next);
		node[address].data = data;
		node[address].next = next;
	}
	int p;
	for(p = s1; p != -1; p = node[p].next){
		node[p].flag = true;
	}
	for(p = s2; p != -1; p = node[p].next){
		if(node[p].flag == true) break;
	}
	if(p != -1){
		printf("%05d\n", p);
	}
	else{
		printf("-1\n");
	}
	return 0;
}