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CheckStraightLine.kt
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CheckStraightLine.kt
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package com.daily.algothrim.leetcode
/**
* 1232. 缀点成线
*
* 在一个 XY 坐标系中有一些点,我们用数组 coordinates 来分别记录它们的坐标,其中 coordinates[i] = [x, y] 表示横坐标为 x、纵坐标为 y 的点。
* 请你来判断,这些点是否在该坐标系中属于同一条直线上,是则返回 true,否则请返回 false。
*
* 输入:coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
* 输出:true
*
* 输入:coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
* 输出:false
*/
class CheckStraightLine {
companion object {
@JvmStatic
fun main(args: Array<String>) {
println(CheckStraightLine().solution(arrayOf(
intArrayOf(1, 2),
intArrayOf(2, 3),
intArrayOf(3, 4),
intArrayOf(4, 5),
intArrayOf(5, 6),
intArrayOf(6, 7)
)))
println(CheckStraightLine().solution(arrayOf(
intArrayOf(1, 1),
intArrayOf(2, 2),
intArrayOf(3, 4),
intArrayOf(4, 5),
intArrayOf(5, 6),
intArrayOf(7, 7)
)))
}
}
fun solution(coordinates: Array<IntArray>): Boolean {
return binary(coordinates, 0, coordinates.size - 1)
}
private fun binary(coordinates: Array<IntArray>, start: Int, end: Int): Boolean {
// 注意 end - 1,代表区间就两个数就不需要判断
if (start < end - 1) {
val mid = (start + end).shr(1)
val startX = coordinates[start][0]
val startY = coordinates[start][1]
val midX = coordinates[mid][0]
val midY = coordinates[mid][1]
val endX = coordinates[end][0]
val endY = coordinates[end][1]
if ((midX - startX).times(endY - midY) != (midY - startY).times(endX - midX)) return false
if (!binary(coordinates, start, mid) || !binary(coordinates, mid, end)) return false
}
return true
}
}