Codeforces Round 741 (Div. 2)
C
Rings
Codeforces
1500
原题
← BD1 →
翻译中…

Frodo was caught by Saruman. He tore a pouch from Frodo's neck, shook out its contents —there was a pile of different rings: gold and silver..."How am I to tell which is the One?!" the mage howled."Throw them one by one into the Cracks of Doom and watch when Mordor falls!"

翻译中…

Somewhere in a parallel Middle-earth, when Saruman caught Frodo, he only found $n$ rings. And the $i$-th ring was either gold or silver. For convenience Saruman wrote down a binary string $s$ of $n$ characters, where the $i$-th character was 0 if the $i$-th ring was gold, and 1 if it was silver.

翻译中…

Saruman has a magic function $f$, which takes a binary string and returns a number obtained by converting the string into a binary number and then converting the binary number into a decimal number. For example, $f(001010) = 10, f(111) = 7, f(11011101) = 221$.

翻译中…

Saruman, however, thinks that the order of the rings plays some important role. He wants to find $2$ pairs of integers $(l_1, r_1), (l_2, r_2)$, such that:

翻译中…
  • $1 \le l_1 \le n$, $1 \le r_1 \le n$, $r_1-l_1+1\ge \lfloor \frac{n}{2} \rfloor$
  • $1 \le l_2 \le n$, $1 \le r_2 \le n$, $r_2-l_2+1\ge \lfloor \frac{n}{2} \rfloor$
  • Pairs $(l_1, r_1)$ and $(l_2, r_2)$ are distinct. That is, at least one of $l_1 \neq l_2$ and $r_1 \neq r_2$ must hold.
  • Let $t$ be the substring $s[l_1:r_1]$ of $s$, and $w$ be the substring $s[l_2:r_2]$ of $s$. Then there exists non-negative integer $k$, such that $f(t) = f(w) \cdot k$.
翻译中…

Here substring $s[l:r]$ denotes $s_ls_{l+1}\ldots s_{r-1}s_r$, and $\lfloor x \rfloor$ denotes rounding the number down to the nearest integer.

翻译中…

Help Saruman solve this problem! It is guaranteed that under the constraints of the problem at least one solution exists.

翻译中…

Input

翻译中…

Each test contains multiple test cases.

翻译中…

The first line contains one positive integer $t$ ($1 \le t \le 10^3$), denoting the number of test cases. Description of the test cases follows.

翻译中…

The first line of each test case contains one positive integer $n$ ($2 \le n \le 2 \cdot 10^4$) — length of the string.

翻译中…

The second line of each test case contains a non-empty binary string of length $n$.

翻译中…

It is guaranteed that the sum of $n$ over all test cases does not exceed $10^5$.

翻译中…

Output

翻译中…

For every test case print four integers $l_1$, $r_1$, $l_2$, $r_2$, which denote the beginning of the first substring, the end of the first substring, the beginning of the second substring, and the end of the second substring, respectively.

翻译中…

If there are multiple solutions, print any.

翻译中…

Note

翻译中…

In the first testcase $f(t) = f(1111) = 15$, $f(w) = f(101) = 5$.

翻译中…

In the second testcase $f(t) = f(111000111) = 455$, $f(w) = f(000111) = 7$.

翻译中…

In the third testcase $f(t) = f(0000) = 0$, $f(w) = f(1000) = 8$.

翻译中…

In the fourth testcase $f(t) = f(11011) = 27$, $f(w) = f(011) = 3$.

翻译中…

In the fifth testcase $f(t) = f(001111) = 15$, $f(w) = f(011) = 3$.

翻译中…

样例

Input #1
7
6
101111
9
111000111
8
10000000
5
11011
6
001111
3
101
30
100000000000000100000000000000
Output #1
3 6 1 3
1 9 4 9
5 8 1 4
1 5 3 5
1 6 2 4
1 2 2 3
1 15 16 30
InputCopy OutputCopy
题目信息
题号
1562C
时间限制
1 s
内存限制
256 MB
标签
构造
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。