PAT(甲级)1038

1038. Recover the Smallest Number (30)

时间限制

400 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

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

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#define ROW 10004
//////////////////////////////////////////////////////////////////////
//TAKE CARE OF STRING COMPARISION
//ESPECIALLY IN CASES SUCH AS 32 321 32132 ETC
//THE KEY POINT IN COMPARISION LIES HERE: SUBSTRCT A SUBSTR FROM THE
//LONGER ONE,COMPARE THE REMAINER AND SUBSTR,IF SUBSTR CONTAIN REMAINDER
//OR REMAINDER CONTAIN SUBSTR, SUBSTRACT RECURRSIVELY UNTIL GOT THE ANSWER
//////////////////////////////////////////////////////////////////////////
using namespace std;

string str[ROW];

char * nonzero(string &str1){
	char *p = &str1[0];
	while(*p !='\0'){
		if(*p !='0') 
		    return p;
		else
		    p++;
	}
	return NULL;
}

bool cmp1(const char *s1,const char *s2);

bool cmp(const string &s1,const string &s2){  //THE KEY TO FENTCH EVERY ELEMENT OF STRING CLAA
	const char *p1=&s1[0];                    //CAN BE USED LIKE THIS!!!
	const char *p2=&s2[0];
    return cmp1(p1,p2);
}

bool cmp1(const char *s1,const char *s2){
	const char *p1 =s1;
	const char *p2=s2;
	while(*p1 != '\0' &&*p2 !='\0'){
		if(*p1 == *p2){
			p1++;
			p2++;
		}else
		    return *p1 <*p2;
	}
	if(*p1 == '\0' && *p2 != '\0'){   //s1 is short
		if(*p2 !=*s1)
		    return *s1 < *p2;
		else
		    return cmp1(s1,p2);
	} 
	if(*p1 != '\0' && *p2 == '\0')   //s2 is short
	    if(*p1 != *s2)
	        return *p1 < *s2;
	    else
	        return cmp1(p1,s2);
}


int main()
{
	int i,N;
	scanf("%d",&N);
	for(i=0;i<N;i++)
	    cin >>str[i];
	std::sort(str,str+N,cmp);
	char *phead;
	for(i=0;i<N;i++)
	{
		phead=nonzero(str[i]);
		if(phead != NULL)
		    break;
	}
	if(i == N)      //IF ALL ARE ZEROS, OUTPUT 0
	{
		cout <<0 <<endl;
		return 0;
	}
	cout <<phead;  //PRINT THE HEAD
	for(i++;i<N;i++)
	    cout <<str[i];
	return 0;
}