AtCoder Beginner Contest 126
E
1 or 2
AtCoder
⌀ 1340
原题
← DF →
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Problem Statement

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There are $N$ cards placed face down in a row. On each card, an integer $1$ or $2$ is written.

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Let $A_i$ be the integer written on the $i$-th card.

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Your objective is to guess $A_1, A_2, ..., A_N$ correctly.

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You know the following facts:

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  • For each $i = 1, 2, ..., M$, the value $A_{X_i} + A_{Y_i} + Z_i$ is an even number.
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You are a magician and can use the following magic any number of times:

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Magic: Choose one card and know the integer $A_i$ written on it. The cost of using this magic is $1$.

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What is the minimum cost required to determine all of $A_1, A_2, ..., A_N$?

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It is guaranteed that there is no contradiction in given input.

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Constraints

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  • All values in input are integers.
  • $2 \leq N \leq 10^5$
  • $1 \leq M \leq 10^5$
  • $1 \leq X_i < Y_i \leq N$
  • $1 \leq Z_i \leq 100$
  • The pairs $(X_i, Y_i)$ are distinct.
  • There is no contradiction in input. (That is, there exist integers $A_1, A_2, ..., A_N$ that satisfy the conditions.)
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Input

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Input is given from Standard Input in the following format:

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N M
X_1 Y_1 Z_1
X_2 Y_2 Z_2
\vdots
X_M Y_M Z_M

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Output

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Print the minimum total cost required to determine all of $A_1, A_2, ..., A_N$.

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样例

Input #1
3 1
1 2 1
Output #1
2
You can determine all of $A_1, A_2, A_3$ by using the magic for the first and third cards.
Input #2
6 5
1 2 1
2 3 2
1 3 3
4 5 4
5 6 5
Output #2
2
Input #3
100000 1
1 100000 100
Output #3
99999
题目信息
题号
abc126_e
时间限制
2 s
内存限制
1024 MB

题面与样例版权归 AtCoder 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。