You're given a list of n strings a1, a2, ..., an. You'd like to concatenate them together in some order such that the resulting string would be lexicographically smallest.
Given the list of strings, output the lexicographically smallest concatenation.
The first line contains integer n — the number of strings (1 ≤ n ≤ 5·104).
Each of the next n lines contains one string ai (1 ≤ |ai| ≤ 50) consisting of only lowercase English letters. The sum of string lengths will not exceed 5·104.
Print the only string a — the lexicographically smallest string concatenation.
4 abba abacaba bcd er
abacabaabbabcder
5 x xx xxa xxaa xxaaa
xxaaaxxaaxxaxxx
3 c cb cba
cbacbc
题意:
给出一些字符串,问如何首位连接,拼接成一个字典序最小的字符串!
题解:
主要是排序,由于之前的一个错误排序思路,在这里,
做这道题的时候拘泥于之前的思路,一直wa,但是确实不知道错在哪里了,经过一系列的测验和考察,发现原来自己的排序思路是错误的
下面的测试数据无法通过
2
1231
123
2
123
1231
本题最正确的方法应该是这样做
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
using namespace std;
int cmp(string a,string b)
{
return a+b<b+a;
}
void slove(string x[],int n)
{
sort(x,x+n,cmp);
for(int i=0;i<n;++i)
{
cout << x[i];
}
printf("\n");
}
int main()
{
int n;string x[50005];
//freopen("shuju.txt","r",stdin);
while(~scanf("%d",&n))
{
for(int i=0;i<n;++i)
{
cin >> x[i];
}
slove(x,n);
}
return 0;
}
如果不用string 类型,字符数组的话可以:
方法来源于一朋友,瞬间感觉碉堡了....两种方法一样,sort 内部排序真奇妙,自己需要学的东西还有很多!
int cmp(node a,node b)
{
return strcmp(strcat(a.s,b.s),strcat(b.s,a.s))<0;
}