Codeforces Round 495 (Div. 2)
B
Sonya and Exhibition
Codeforces
1300
原题
← AC →
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Sonya decided to organize an exhibition of flowers. Since the girl likes only roses and lilies, she decided that only these two kinds of flowers should be in this exhibition.

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There are $n$ flowers in a row in the exhibition. Sonya can put either a rose or a lily in the $i$-th position. Thus each of $n$ positions should contain exactly one flower: a rose or a lily.

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She knows that exactly $m$ people will visit this exhibition. The $i$-th visitor will visit all flowers from $l_i$ to $r_i$ inclusive. The girl knows that each segment has its own beauty that is equal to the product of the number of roses and the number of lilies.

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Sonya wants her exhibition to be liked by a lot of people. That is why she wants to put the flowers in such way that the sum of beauties of all segments would be maximum possible.

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Input

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The first line contains two integers $n$ and $m$ ($1\leq n, m\leq 10^3$) — the number of flowers and visitors respectively.

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Each of the next $m$ lines contains two integers $l_i$ and $r_i$ ($1\leq l_i\leq r_i\leq n$), meaning that $i$-th visitor will visit all flowers from $l_i$ to $r_i$ inclusive.

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Output

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Print the string of $n$ characters. The $i$-th symbol should be «0» if you want to put a rose in the $i$-th position, otherwise «1» if you want to put a lily.

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If there are multiple answers, print any.

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Note

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In the first example, Sonya can put roses in the first, fourth, and fifth positions, and lilies in the second and third positions;

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  • in the segment $[1\ldots3]$, there are one rose and two lilies, so the beauty is equal to $1\cdot 2=2$;
  • in the segment $[2\ldots4]$, there are one rose and two lilies, so the beauty is equal to $1\cdot 2=2$;
  • in the segment $[2\ldots5]$, there are two roses and two lilies, so the beauty is equal to $2\cdot 2=4$.
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The total beauty is equal to $2+2+4=8$.

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In the second example, Sonya can put roses in the third, fourth, and sixth positions, and lilies in the first, second, and fifth positions;

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  • in the segment $[5\ldots6]$, there are one rose and one lily, so the beauty is equal to $1\cdot 1=1$;
  • in the segment $[1\ldots4]$, there are two roses and two lilies, so the beauty is equal to $2\cdot 2=4$;
  • in the segment $[4\ldots6]$, there are two roses and one lily, so the beauty is equal to $2\cdot 1=2$.
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The total beauty is equal to $1+4+2=7$.

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样例

Input #1
5 3
1 3
2 4
2 5
Output #1
01100
InputCopy OutputCopy
Input #2
6 3
5 6
1 4
4 6
Output #2
110010
InputCopy OutputCopy
题目信息
题号
1004B
时间限制
1 s
内存限制
256 MB
标签
构造
贪心
模拟
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。