Codeforces B. String Priority Queue

Links: Http://codeforces.com/contest/128/problem/B

B. StringTime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard output

The IT lesson Anna and Maria learned about the lexicographic order.

Stringxis lexicographically less than stringy, if eitherxis a prefix ofy(and x? ≠? y ), or there exists suchI(1?≤? i? ≤? min (| x|,?| y|)), that xi? <? y I , and for anyJ(1?≤? J. < I ) xj? =? y J . Here| a|Denotes the length of the stringa. The lexicographic comparison of strings is implemented by operator < in modern programming languages??.

The teacher gave Anna and Maria homework. She gave them a string of lengthN. They should write out all substrings of the given string, including the whole initial string, and the equal substrings (fo R example, one should write out the following substrings from the string "AaB": "a", "a", "AA", "AB", "AaB", "b"). The resulting strings should is sorted in the lexicographical order. The cunning teacher doesn ' t want to check all these strings. That's why she's said to findk-th string from the list. Help Anna and Maria do the homework.

Input

The first line contains a non-empty string that is only consists of small Latin letters ("a"-"Z"), whose length does not exceedTen5 . The second line contains the only integerk(1?≤? k. ≤?105 ).

Output

Print the string Anna and Maria need-the K-th (in the lexicographical order) substring of the given string. If The total number of substrings are less than K, print a string saying "No such line." (without the quotes).

Sample Test (s) input

Aa2

Output

A

Input

Abc5

Output

Bc

Input

Abab7

Output

B

Note

In the second sample before string "BC" Follow strings "a", "ab", "ABC", "b".

Test instructions: Dictionary ordering substring to find the nth size in the substring.

Practice: You can use a priority queue because you find up to the 100,000th largest. First put in a single. Then constantly remove the smallest, then add a letter after it, and then put it back in the queue. Len in the queue, up to n times, so the complexity of log (len) *n.

But vs2010 's priority queue seems to be slow. Another topic also used in the priority queue, vs2010 run for several minutes to run out of data, CB can run seconds. So do not pay vs2010, otherwise it will time out.

#pragma COMMENT (linker, "/stack:102400000,102400000") #include <stdio.h> #include <stdlib.h> #include < string.h> #include <limits.h> #include <malloc.h> #include <ctype.h> #include <math.h># Include <string> #include <iostream> #include <algorithm>using namespace std; #include <stack># Include <queue> #include <vector> #include <deque> #include <set> #include <map>struct Point{int id;string Ss;bool operator < (const point &b) Const{return ss>b.ss;}}; Char Str[100010];int main () {int n;scanf ("%s%d", str,&n);//n>>str>>n;priority_queue<point>q; int Len=strlen (str); for (int. i=0;str[i];i++) {point tem;tem.ss= ""; Tem.ss=str[i];tem.id=i;q.push (TEM);} int Id=0;point ans;while (!q.empty ()) {point tem=q.top (); Q.pop (); id++;if (id==n) {ans=tem;break;} Tem.id++;if (Tem.id<len) {Tem.ss+=str[tem.id];q.push (TEM);}} if (id!=n) {puts ("No such line.");} Else{cout<<ans.ss<<endl;} return 0;}

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Codeforces B. String Priority Queue