max_points_on_a_line

Author: hitzzc

README.md

@@ -132,6 +132,7 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [146. LRU Cache](https://github.com/hitzzc/go-leetcode/tree/master/lru_cache)
 #### [147. insertion sort list](https://github.com/hitzzc/go-leetcode/tree/master/insertion_sort_list)
 #### [148. sort list](https://github.com/hitzzc/go-leetcode/tree/master/sort_list)
+#### [149. Max Points on a Line](https://github.com/hitzzc/go-leetcode/tree/master/max_points_on_a_line)
 
 
 

max_points_on_a_line/max_points_on_a_line.go

@@ -0,0 +1,40 @@
+package max_points_on_a_line
+
+type Point struct {
+	X int
+	Y int
+}
+
+func maxPoints(points []Point) int {
+	if len(points) < 3 {
+		return len(points)
+	}
+	var max int
+	for i := range points {
+		verticalNum := 0
+		equalNum := 0
+		m := map[float64]int{}
+		for j := range points {
+			if i == j {
+				continue
+			}
+			if points[i].X == points[j].X && points[i].Y == points[j].Y {
+				equalNum++
+			} else if points[i].X == points[j].X {
+				verticalNum++
+			} else {
+				ratio := float64(points[i].Y-points[j].Y) / float64(points[i].X-points[j].X)
+				m[ratio]++
+			}
+		}
+		if verticalNum+equalNum > max {
+			max = verticalNum + equalNum
+		}
+		for k := range m {
+			if m[k]+equalNum > max {
+				max = m[k] + equalNum
+			}
+		}
+	}
+	return max + 1
+}