AtCoder Beginner Contest 153
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Problem Statement
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Silver Fox is fighting with $N$ monsters.
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The monsters are standing in a row, and we can assume them to be standing on a number line. The $i$-th monster, standing at the coordinate $X_i$, has the health of $H_i$.
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Silver Fox can use bombs to attack the monsters. Using a bomb at the coordinate $x$ decreases the healths of all monsters between the coordinates $x-D$ and $x+D$ (inclusive) by $A$. There is no way other than bombs to decrease the monster's health.
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Silver Fox wins when all the monsters' healths become $0$ or below.
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Find the minimum number of bombs needed to win.
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Constraints
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$1 \leq N \leq 2 \times 10^5$$0 \leq D \leq 10^9$$1 \leq A \leq 10^9$$0 \leq X_i \leq 10^9$$1 \leq H_i \leq 10^9$$X_i$are distinct.- All values in input are integers.
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Input
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Input is given from Standard Input in the following format:
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N D A
X_1 H_1
:
X_N H_N翻译中…
Output
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Print the minimum number of bombs needed to win.
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样例
Input #1
3 3 2
1 2
5 4
9 2
Output #1
2
First, let us use a bomb at the coordinate $4$ to decrease the first and second monsters' health by $2$.
Then, use a bomb at the coordinate $6$ to decrease the second and third monsters' health by $2$.
Now, all the monsters' healths are $0$. We cannot make all the monsters' health drop to $0$ or below with just one bomb.
Input #2
9 4 1
1 5
2 4
3 3
4 2
5 1
6 2
7 3
8 4
9 5
Output #2
5
We should use five bombs at the coordinate $5$.
Input #3
3 0 1
300000000 1000000000
100000000 1000000000
200000000 1000000000
Output #3
3000000000
Watch out for overflow.
题目信息
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。