URAL 1242 Werewolf (DFS)

#include <stdio.h>
#define MAX_VILLAGERS 1000

int numOfVillagers;
typedef struct Relative{
	int villager;
	int next;
}Relative;
Relative relativeArray[2 * MAX_VILLAGERS + 1];
int relativeNum;
int ancestorLastAdded[MAX_VILLAGERS + 1];
int descendantLastAdded[MAX_VILLAGERS + 1];
int isHuman[MAX_VILLAGERS + 1];


void addRelative(int head, int relativeLastAdded[], int relative){
	relativeNum++;
	relativeArray[relativeNum].villager = relative;
	relativeArray[relativeNum].next = relativeLastAdded[head];
	relativeLastAdded[head] = relativeNum;
}
void excludeRelatives(int victim, int relativeLastAdded[]){
	isHuman[victim] = 1;
	int relativeIndex;
	for (relativeIndex = relativeLastAdded[victim]; relativeIndex != 0; relativeIndex = relativeArray[relativeIndex].next){
		int villager = relativeArray[relativeIndex].villager;
		//只会单单往ancestor或者单单往descendant深搜
		excludeRelatives(villager, relativeLastAdded);
	}
}

int main(){

	scanf("%d", &numOfVillagers);
	char str[6];
	//注意输入处理
	while (scanf("%s", str) != EOF && str[0] != 'B'){
		int child = 0;
		int i;
		for (i = 0; str[i] != '\0'; i++)
			child = child * 10 + str[i] - '0';
		int parent;
		scanf("%d", &parent);
		addRelative(child, ancestorLastAdded, parent);
		addRelative(parent, descendantLastAdded, child);
	}

	int victim;
	while (scanf("%d", &victim) != EOF){
		//无需再用的数据甭存储，输入后立马处理
		excludeRelatives(victim, ancestorLastAdded);
		excludeRelatives(victim, descendantLastAdded);
	}

	int found = 0;
	int villager;
	for (villager = 1; villager <= numOfVillagers; villager++)
		if (!isHuman[villager]){
			printf("%d ", villager);
			found = 1;
		}
	printf("%s", found ? "\n" : "0\n");
	
	return 0;
}