Python实现Pat 1032. Sharing (25)-蒲公英云

Python实现Pat 1032. Sharing (25)

题目

Given a collection of number segments, you are supposed to recover the smallest number from them. For example, given {32, 321, 3214, 0229, 87}, we can recover many numbers such like 32-321-3214-0229-87 or 0229-32-87-321-3214 with respect to different orders of combinations of these segments, and the smallest number is 0229-321-3214-32-87.

Input Specification:

Each input file contains one test case. Each case gives a positive integer N (<=10000) followed by N number segments. Each segment contains a non-negative integer of no more than 8 digits. All the numbers in a line are separated by a space.

Output Specification:

For each test case, print the smallest number in one line. Do not output leading zeros.

Sample Input:
5 32 321 3214 0229 87
Sample Output:
22932132143287

解答

排序题，关键在于字符串的大小比较。比较两个字符串大小时如32和321，如果有相同前缀，则删除较长的字符串中的前缀，并比较剩下的数的大小，即32和321的比较结果应该是32和1的比较结果。

from functools import cmp_to_key
def cmpt(s1,s2):
     len1=len(s1)
     len2=len(s2)
     maxl=max(len1,len2)
     for i in range(maxl):
         if s1[i%len1]!=s2[i%len2]:
             return  int(s1[i%len1])-int(s2[i%len2])
     else:
         return 0
line0=input().split(' ')[1:]
line0.sort(key=cmp_to_key(cmpt))
num=''
for e in line0:
    num+=e
count=0
#剔除无效的‘0’
for e in num:
    if e=='0':
        count+=1
    else:
        break
num=num[count:]
#特殊情况
if not num:
    num='0'
print (num)