Package g0201_0300.s0218_the_skyline_problem

Class Solution

java.lang.Object
g0201_0300.s0218_the_skyline_problem.Solution
public class Solution extends Object
218 - The Skyline Problem.<p>Hard</p> <p>A city&rsquo;s <strong>skyline</strong> is the outer contour of the silhouette formed by all the buildings in that city when viewed from a distance. Given the locations and heights of all the buildings, return <em>the <strong>skyline</strong> formed by these buildings collectively</em>.</p> <p>The geometric information of each building is given in the array <code>buildings</code> where <code>buildings[i] = [left<sub>i</sub>, right<sub>i</sub>, height<sub>i</sub>]</code>:</p> <ul> <li><code>left<sub>i</sub></code> is the x coordinate of the left edge of the <code>i<sup>th</sup></code> building.</li> <li><code>right<sub>i</sub></code> is the x coordinate of the right edge of the <code>i<sup>th</sup></code> building.</li> <li><code>height<sub>i</sub></code> is the height of the <code>i<sup>th</sup></code> building.</li> </ul> <p>You may assume all buildings are perfect rectangles grounded on an absolutely flat surface at height <code>0</code>.</p> <p>The <strong>skyline</strong> should be represented as a list of &ldquo;key points&rdquo; <strong>sorted by their x-coordinate</strong> in the form <code>[[x<sub>1</sub>,y<sub>1</sub>],[x<sub>2</sub>,y<sub>2</sub>],&hellip;]</code>. Each key point is the left endpoint of some horizontal segment in the skyline except the last point in the list, which always has a y-coordinate <code>0</code> and is used to mark the skyline&rsquo;s termination where the rightmost building ends. Any ground between the leftmost and rightmost buildings should be part of the skyline&rsquo;s contour.</p> <p><strong>Note:</strong> There must be no consecutive horizontal lines of equal height in the output skyline. For instance, <code>[...,[2 3],[4 5],[7 5],[11 5],[12 7],...]</code> is not acceptable; the three lines of height 5 should be merged into one in the final output as such: <code>[...,[2 3],[4 5],[12 7],...]</code></p> <p><strong>Example 1:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2020/12/01/merged.jpg" alt="" /></p> <p><strong>Input:</strong> buildings = [[2,9,10],[3,7,15],[5,12,12],[15,20,10],[19,24,8]]</p> <p><strong>Output:</strong> [[2,10],[3,15],[7,12],[12,0],[15,10],[20,8],[24,0]]</p> <p><strong>Explanation:</strong></p> <pre><code> Figure A shows the buildings of the input. Figure B shows the skyline formed by those buildings. The red points in figure B represent the key points in the output list. </code></pre> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> buildings = [[0,2,3],[2,5,3]]</p> <p><strong>Output:</strong> [[0,3],[5,0]]</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= buildings.length <= 10<sup>4</sup></code></li> <li><code>0 <= left<sub>i</sub> < right<sub>i</sub> <= 2<sup>31</sup> - 1</code></li> <li><code>1 <= height<sub>i</sub> <= 2<sup>31</sup> - 1</code></li> <li><code>buildings</code> is sorted by <code>left<sub>i</sub></code> in non-decreasing order.</li> </ul>

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