Spoj->PhoeLst Problem
Narendra Chennupati
can you suggest a best data structure & algo to solve this problem?
Problem code: PHONELST
Phone List Given a list of phone numbers, determine if it is consistent in the sense that no number is the prefix of another. Let’s say the phone catalogue listed these numbers:
• Emergency 911
• Alice 97 625 999
• Bob 91 12 54 26
In this case, it’s not possible to call Bob, because the central would direct your call to the emergency line as soon as you had dialled the first three digits of Bob’s phone number. So this list would not be consistent.
Input
The first line of input gives a single integer, 1 <= t <= 40, the number of test cases. Each test case starts with n, the number of phone numbers, on a separate line, 1 <= n <= 10000. Then follows n lines with one unique phone number on each line. A phone number is a sequence of at most ten digits.
Output
For each test case, output “YES” if the list is consistent, or “NO” otherwise.
Example
Input:
2
3
911
97625999
91125426
5
113
12340
123440
12345
98346
Output:
NO
YES
Mickey
How about tries? when string are involved and we need to search by
longest prefix match tries is the choice. http://en.wikipedia.org/wiki/Trie
Regards,
Jyoti
On May 19, 2:00 pm, Narendra Chennupati <narendra....@gmail.com>
wrote:
> 3
> 911
> 97625999
> 91125426
> 5
> 113
> 12340
> 123440
> 12345
> 98346
>
> NO
> YES
Akhil Bhiwal
friend Satish Eerpini:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
int input(char **arr, int n);
int match(char **arr, int n);
int min(int a, int b)
{
if(a > b)
return b;
return a;
}
int main()
{
char phoneno[10], **arr, i;
int n, count = 0;
printf("How many phone no: ");
scanf("%d", &n);
arr = (char **)malloc(sizeof(int)*n);
while(count < n){
arr[count] = (char *)malloc(10*sizeof(char));
scanf("%s", arr[count++]);
}
if(match(arr, n))
{
printf("Invalid list\n");
return 0;
}
printf("Valid list\n");
return 0;
}
int match(char **arr, int n)
{
int i, j, len, len1, len2;
for(i = 0; i < n; i++)
for(j = i+1; j < n; j++)
{
len1 = strlen(arr[i]);
len2 = strlen(arr[j]);
len = min(len1, len2);
if(!strncmp(arr[i], arr[j], len))
return 1;
}
return 0;
}
As suggested by Jyoti, Trie could be a better option (I had never
heard this structure until I saw his post, so did not implement it in
my solution).
On May 24, 11:26 am, Mickey <jyoti.mic...@gmail.com> wrote:
> Hi Naren,
>
> How about tries? when string are involved and we need to search by