overlapping rectangles

main.go

package main

import (
	"fmt"
)

type Rectangle struct {
	startingX int
	startingY int
	width     int
	height    int
}

func (r Rectangle) Points() (out [][]int) {
	for w := r.startingX; w <= r.startingX+r.width; w++ {
		couple := []int{}
		for h := r.startingY; h >= r.startingY-r.height; h-- {
			couple = append(couple, w)
			couple = append(couple, h)
			out = append(out, couple)
			couple = []int{}
		}
	}
	return
}

func CommonPoints(a, b Rectangle) (out [][]int) {
	for _, p := range a.Points() {
		for _, c := range b.Points() {
			if p[0] == c[0] && p[1] == c[1] {
				out = append(out, p)
			}
		}
	}
	return
}

func CalcAreaFromPoints(points [][]int) int {
	if len(points) == 0 {
		return 0
	}
	minX := points[0][0]
	for p := range points[1:] {
		if points[p][0] < minX {
			minX = points[p][0]
		}
	}
	maxX := points[0][0]
	for p := range points[1:] {
		if points[p][0] > maxX {
			maxX = points[p][0]
		}
	}
	minY := points[0][1]
	for p := range points[1:] {
		if points[p][1] < minY {
			minY = points[p][1]
		}
	}
	maxY := points[0][1]
	for p := range points[1:] {
		if points[p][1] > maxY {
			maxY = points[p][1]
		}
	}
	return (maxX - minX) * (maxY - minY)
}

func main() {
	A := Rectangle{
		startingX: 1,
		startingY: 4,
		width:     3,
		height:    3,
	}

	B := Rectangle{
		startingX: 0,
		startingY: 5,
		width:     4,
		height:    3,
	}

	fmt.Println("Points of A: ", A.Points())
	fmt.Println("Points of B: ", B.Points())

	internal := CommonPoints(A, B)
	fmt.Println("Common points: ", internal)

	commonArea := CalcAreaFromPoints(internal)
	fmt.Println("Common area size: ", commonArea)
}