200591: [AtCoder]ARC059 D - Unbalanced
Description
Score : $400$ points
Problem Statement
Given a string $t$, we will call it unbalanced if and only if the length of $t$ is at least $2$, and more than half of the letters in $t$ are the same. For example, both voodoo
and melee
are unbalanced, while neither noon
nor a
is.
You are given a string $s$ consisting of lowercase letters. Determine if there exists a (contiguous) substring of $s$ that is unbalanced. If the answer is positive, show a position where such a substring occurs in $s$.
Constraints
- $2 ≦ |s| ≦ 10^5$
- $s$ consists of lowercase letters.
Partial Score
- $200$ points will be awarded for passing the test set satisfying $2 ≦ N ≦ 100$.
Input
The input is given from Standard Input in the following format:
$s$
Output
If there exists no unbalanced substring of $s$, print -1 -1
.
If there exists an unbalanced substring of $s$, let one such substring be $s_a s_{a+1} ... s_{b}$ $(1 ≦ a < b ≦ |s|)$, and print $a$ $b$
. If there exists more than one such substring, any of them will be accepted.
Sample Input 1
needed
Sample Output 1
2 5
The string $s_2 s_3 s_4 s_5$ $=$ eede
is unbalanced. There are also other unbalanced substrings. For example, the output 2 6
will also be accepted.
Sample Input 2
atcoder
Sample Output 2
-1 -1
The string atcoder
contains no unbalanced substring.