UVa 10382 - Watering Grass（贪心算法，区间覆盖问题）

最新推荐文章于 2021-03-22 21:05:00 发布

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最新推荐文章于 2021-03-22 21:05:00 发布 · 4.1k 阅读

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#贪心算法 #区间覆盖

该博客讨论了如何应用贪心算法解决UVa 10382问题，即在覆盖一定长度草地的区间覆盖问题。通过将问题转化为区间覆盖，舍去无法覆盖的洒水器，并按覆盖范围升序排列，逐步找到能覆盖最远区域的洒水器，以求得覆盖整个草地所需的最小洒水器数量。如果无法覆盖所有草地，则输出-1。

Problem E
Watering Grass
Input: standard input
Output: standard output
Time Limit: 3 seconds

n sprinklers are installed in a horizontal strip of grass l meters long andw meters wide. Each sprinkler is installed at the horizontal center line of the strip. For each sprinkler we are given its position as the distance from the left end of the center line and its radius of operation.

What is the minimum number of sprinklers to turn on in order to water the entire strip of grass?

Input

Input consists of a number of cases. The first line for each case contains integer numbersn, l and w with n <= 10000. The next n lines contain two integers giving the position of