【PAT甲级】1032. Sharing (25)

#include <stdio.h>

int main(int argc, char *argv[]) {
int list[100000] = {0};
int n;
int arr1;
int arr2;
int set[100000] = {0};
int i;
int out = -1;
scanf("%d %d %d", &arr1, &arr2, &n);
for (i = 0; i < n; i++) {
int a1, a2;
scanf("%d %*c %d", &a1, &a2);
list[a1] = a2;
}
int p = arr1;
while (p != -1) {
set[p] = 1;
p = list[p];
}
p = arr2;
while (p != -1) {
if (set[p] == 1) {
out = p;
break;
}
p = list[p];
}
if (out != -1) printf("%05d\n", out);
else printf("-1\n");
return 0;
}