问题 : You are my brother
时间限制: 1 Sec 内存限制: 128 MB
题目描述
Little A gets to know a new friend, Little B, recently. One day, they realize that they are family 500 years ago. Now, Little A wants to know whether Little B is his elder, younger or brother.
输入
There are multiple test cases.
For each test case, the first line has a single integer, n (n<=1000). The next n lines have two integers a and b (1<=a,b<=2000) each, indicating b is the father of a. One person has exactly one father, of course. Little A is numbered 1 and Little B is numbered 2.
Proceed to the end of file.
输出
For each test case, if Little B is Little A’s younger, print “You are my younger”. Otherwise, if Little B is Little A’s elder, print “You are my elder”. Otherwise, print “You are my brother”. The output for each test case occupied exactly one line.
样例输入
5 1 3 2 4 3 5 4 6 5 6 6 1 3 2 4 3 5 4 6 5 7 6 7
样例输出
You are my elder You are my brother
解题思路
根据所给的数对,判断1,2分别组成的链的长短。
#include <stdio.h> #include <string.h> int main() { int n, a, b; int s[2010]; while (~scanf("%d", &n)) { memset(s, 0, sizeof(s)); for (int i = 0; i < n; i++) { scanf("%d%d", &a, &b); s[a] = b; } a = 1; b = 2; while (s[a] && s[b]) { a = s[a]; b = s[b]; } if (!s[a] && s[b]) puts("You are my younger"); else if (!s[a] && !s[b]) puts("You are my brother"); else puts("You are my elder"); } return 0; }