PAT 1051 Pop Sequence (25分) 模拟入栈

Given a stack which can keep M numbers at most. Push N numbers in the order of 1, 2, 3, ..., N and pop randomly. You are supposed to tell if a given sequence of numbers is a possible pop sequence of the stack.


PAT1050 String Subtraction (20分) 用布尔数组

Given two strings S​1​​ and S​2​​ , S=S​1​​ −S​2​​ is defined to be the remaining string after taking all the characters in S​2​​ from S​1​​ . Your task is simply to calculate S1​​​ −S​2​​ for any given strings.


PAT 1048 Find Coins (25分) 硬币面值做数组下标即排序

Eva loves to collect coins from all over the universe, including some other planets like Mars. One day she visited a universal shopping mall which could accept all kinds of coins as payments. However, there was a special requirement of the payment: for each bill, she could only use exactly two coins to pay the exact amount.


PAT 1046 Shortest Distance (20分)

The task is really simple: given N exits on a highway which forms a simple cycle, you are supposed to tell the shortest distance between any pair of exits.


PAT1045 Favorite Color Stripe (30分) 动态规划

Eva is trying to make her own color stripe out of a given one. She would like to keep only her favorite colors in her favorite order by cutting off those unwanted pieces and sewing the remaining parts together to form her favorite color stripe.