[PAT解题报告] Sharing

#include <cstdio>
#include <cstring>
#include <string>
using namespace std;

int add[100002];

int main() {
int x,y,z;
    for (scanf("%d%d%d",&x,&y,&z);z;--z) {
        int where;
        char s[10];
        int to;
        scanf("%d%s%d",&where,s,&to);
        add[where] = to;
    }
    int lenx = 0;
    for (int i = x; i >= 0; ++lenx, i = add[i])
    ;
    int leny = 0;
    for (int i = y; i >= 0; ++leny, i = add[i])
    ;
    for (int i = lenx - leny; i > 0; --i, x = add[x])
    ;
    for (int i = leny - lenx; i > 0; --i, y = add[y])
    ;
    for (; (x >= 0) && (y >= 0) && (x != y); x = add[x], y = add[y])
    ;
    if (x >= 0) {
        printf("%05d\n",x);
    }
    else {
        puts("-1");
    }
    return 0;
}