Prefix Removals (Codeforces 1652B)
Tags: Others, strings

You are given a string $$$s$$$ consisting of lowercase letters of the English alphabet. You must perform the following algorithm on $$$s$$$:  Let $$$x$$$ be the length of the longest prefix of $$$s$$$ which occurs somewhere else in $$$s$$$ as a contiguous substring (the other occurrence may also intersect the prefix). If $$$x = 0$$$, break. Otherwise, remove the first $$$x$$$ characters of $$$s$$$, and repeat. A prefix is a string consisting of several first letters of a given string, without any reorders. An empty prefix is also a valid prefix. For example, the string "abcd" has 5 prefixes: empty string, "a", "ab", "abc" and "abcd".For instance, if we perform the algorithm on $$$s =$$$ "abcabdc",   Initially, "ab" is the longest prefix that also appears somewhere else as a substring in $$$s$$$, so $$$s =$$$ "cabdc" after $$$1$$$ operation.  Then, "c" is the longest prefix that also appears somewhere else as a substring in $$$s$$$, so $$$s =$$$ "abdc" after $$$2$$$ operations.  Now $$$x=0$$$ (because there are no non-empty prefixes of "abdc" that also appear somewhere else as a substring in $$$s$$$), so the algorithm terminates. Find the final state of the string after performing the algorithm.

Input: The first line contains a single integer $$$t$$$ ($$$1 \le t \le 10^4$$$) — the number of test cases.This is followed by $$$t$$$ lines, each containing a description of one test case. Each line contains a string $$$s$$$. The given strings consist only of lowercase letters of the English alphabet and have lengths between $$$1$$$ and $$$2 \cdot 10^5$$$ inclusive.It is guaranteed that the sum of the lengths of $$$s$$$ over all test cases does not exceed $$$2 \cdot 10^5$$$.

Output: For each test case, print a single line containing the string $$$s$$$ after executing the algorithm. It can be shown that such string is non-empty.

Note: The first test case is explained in the statement.In the second test case, no operations can be performed on $$$s$$$.In the third test case,   Initially, $$$s =$$$ "bbbbbbbbbb".  After $$$1$$$ operation, $$$s =$$$ "b". In the fourth test case,   Initially, $$$s =$$$ "codeforces".  After $$$1$$$ operation, $$$s =$$$ "odeforces".  After $$$2$$$ operations, $$$s =$$$ "deforces". 

Sample Inputs:
6
abcabdc
a
bbbbbbbbbb
codeforces
cffcfccffccfcffcfccfcffccffcfccf
zyzyzwxxyyxxyyzzyzzxxwzxwywxwzxxyzzw

Sample Outputs:
abdc
a
b
deforces
cf
xyzzw

Solution (Python):
t = int(input())
for i in range(t):
    s = str(input())
    s_1 = set(s)
    l = len(s_1)
    R = s[-l:]
    d = s_1 - set(R)
    if len(d) != 0:
        s_2 = s[::-1]
        mx = 0
        for i in d:
            mx = max(mx, s_2.find(i))
        R = s[-(mx + 1):]
    print(R)

Solution (Python):
t = int(input())
for i in range(t):
    s = input()
    sl = list(set(s))
    x = len(s)
    for i in sl:
        x = min(x, s.rindex(i))
    print(s[x:])

Solution (Python):
def main():
    s = input()
    kek = [10 ** 9] * 26
    for i in range(len(s)):
        c = s[i]
        kek[ord(c) - ord('a')] = i
    i = min(kek)
    res = s[i:]
    print(res)
for _ in range(int(input())):
    main()