UVa 10905 Children's Game （ 贪心 ）

Children's Game

Time Limit:3000MS    Memory Limit:0KB    64bit IO Format:%lld & %llu

Submit     Status

Description

4^thIIUCInter-University Programming Contest, 2005

A

Children’s Game

Input: standard input
Output: standard output

Problemsetter: Md. Kamruzzaman

There are lots of number games for children. These games are pretty easy to play but not so easy to make. We will discuss about an interesting game here. Each player will be givenN positive integer. (S)He can make a big integer by appending those integers after one another. Such as if there are 4 integers as 123, 124, 56, 90 then the following integers can be made – 1231245690, 1241235690, 5612312490, 9012312456, 9056124123 etc. In fact 24 such integers can be made. But one thing is sure that 9056124123 is the largest possible integer which can be made.

You may think that it’s very easy to find out the answer but will it be easy for a child who has just got the idea of number?

Input

Each input starts with a positive integer N (≤ 50). In next lines there areN positive integers. Input is terminated byN = 0, which should not be processed.

Output

For each input set, you have to print the largest possible integer which can be made by appending all theN integers.

Sample Input

Output for Sample Input

4
123 124 56 90
5
123 124 56 90 9
5
9 9 9 9 9
0

9056124123
99056124123
99999

题意：给n个数，求n个数连接起来能组成的最大数。

心得：水题一道~~~这么简单的题，唉.................我这水平太水了！！！竟然傻呵呵的自己去写比较函数............结果也没写出来。。。关键时刻，竟然忘了，强大的string可以直接用’+‘连接在一起，给跪了.....................

分析：直接把各个数用string来存，用sort排序,主要的技术活在于自己写sort的cmp函数，在cmp里判断 a+b 与 b+a 的字典序大小即可。详见代码

AC代码：

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <set>#include <map>#include <string>#include <cmath>#include <cstdlib>#include <ctime>#define INF 0x7fffffffusing namespace std;const int maxn = 1000 + 10;string s[maxn];bool cmp(const string a,const string b){    return a+b > b+a;         // 传说中的技术活，比较两种连接顺序的字典序大小}int main(){    int n;    while(scanf("%d",&n)!=EOF && n)    {        for(int i = 0; i < n; i++)            cin>>s[i];        sort(s,s+n,cmp);            //把所有的string排序        for(int i=0;i<n;i++)        //直接把排序后的所有string挨个输出            cout<<s[i];        cout<<endl;    }    return 0;}