2014西安网络预选赛1002（后缀数组求第K大的子串）hdu5008

Boring String Problem

Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 272    Accepted Submission(s): 65

Problem Description

In this problem, you are given a string s and q queries.

For each query, you should answer that when all distinct substrings of string s were sorted lexicographically, which one is the k-th smallest. 

A substring s _i...j of the string s = a ₁a ₂ ...a _n(1 ≤ i ≤ j ≤ n) is the string a _ia _i+1 ...a _j. Two substrings s _x...y and s _z...w are cosidered to be distinct if s _x...y ≠ S _z...w

 

Input

The input consists of multiple test cases.Please process till EOF. 

Each test case begins with a line containing a string s(|s| ≤ 10 ⁵) with only lowercase letters.

Next line contains a postive integer q(1 ≤ q ≤ 10 ⁵), the number of questions.

q queries are given in the next q lines. Every line contains an integer v. You should calculate the k by k = (l⊕r⊕v)+1(l, r is the output of previous question, at the beginning of each case l = r = 0, 0 < k < 2 ⁶³, “⊕” denotes exclusive or)

 

Output

For each test case, output consists of q lines, the i-th line contains two integers l, r which is the answer to the i-th query. (The answer l,r satisfies that s _l...r is the k-th smallest and if there are several l,r available, ouput l,r which with the smallest l. If there is no l,r satisfied, output “0 0”. Note that s _1...n is the whole string)

 

Sample Input

    
    
    
    

     
     
     
     aaa
4
0
2
3
5
    
    
    
    

 

Sample Output

    
    
    
    

     
     
     
     1 1
1 3
1 2
0 0
    
    
    
    

题意：找出第k大的子串，有多种情况要取l最小的一个

思路：比赛的时候看完题目以后大概知道是后缀数组，就没细想了，因为还有其它过的人更多的题没做出来= =

            首先注意后缀数组可以求出到第i个后缀一共有多少种不同的子串

            先不考虑前面的影响，而第i个后缀不同的子串的个数就等于在该后缀上找前缀的个数，就等于该后缀的长度，即cnt=n-sa[i]

            而这个cnt是包含了与上一个名次的后缀前面一样的串的个数，所以还要减去这部分（恰好等于height[i]），即cnt=cnt - height[i]

            然后对于查询，只需要二分找到第一个满足的sa[i]，那么就可以从sa[i]开始往后枚举最小的下标，因为后面可能存在一样的串且下标更小