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-rw-r--r--2021/17/example1
-rw-r--r--2021/17/first.go69
-rw-r--r--2021/17/input1
-rw-r--r--2021/17/second.go54
4 files changed, 125 insertions, 0 deletions
diff --git a/2021/17/example b/2021/17/example
new file mode 100644
index 0000000..a07e02d
--- /dev/null
+++ b/2021/17/example
@@ -0,0 +1 @@
+target area: x=20..30, y=-10..-5
diff --git a/2021/17/first.go b/2021/17/first.go
new file mode 100644
index 0000000..529bbcf
--- /dev/null
+++ b/2021/17/first.go
@@ -0,0 +1,69 @@
+package main
+
+import (
+ "bufio"
+ "fmt"
+ "os"
+ "strconv"
+ "strings"
+)
+
+type vector struct {
+ x, y int
+}
+
+func main() {
+ scanner := bufio.NewScanner(os.Stdin)
+ scanner.Scan()
+ line := scanner.Text()
+ elts := strings.Split(line, "..")
+ eltsx1 := strings.Split(elts[0], "=")
+ x1, _ := strconv.Atoi(eltsx1[1])
+ eltsx2 := strings.Split(elts[1], ",")
+ x2, _ := strconv.Atoi(eltsx2[0])
+ eltsy1 := strings.Split(elts[1], "=")
+ y1, _ := strconv.Atoi(eltsy1[1])
+ y2, _ := strconv.Atoi(elts[2])
+
+ // We need to calculate which steps and horizontal speeds can hit the target box
+ x := 0
+ vx := 0 // its a vx max more than a vx
+ i := 1
+ for {
+ if x+vx+1 <= x2 {
+ vx += 1
+ x += vx
+ i++
+ } else {
+ break
+ }
+ }
+
+ hmax := 0
+ for nextVy := 0; nextVy < 10000; nextVy++ {
+ y := 0
+ vy := nextVy
+ tmpHmax := 0
+ j := 0
+ for {
+ if y+vy >= y1 {
+ y += vy
+ vy--
+ j++
+ } else {
+ break
+ }
+ if tmpHmax < y {
+ tmpHmax = y
+ }
+ }
+ if y >= y1 && y <= y2 && hmax < tmpHmax {
+ hmax = tmpHmax
+ fmt.Printf("h=%d, y=%d, vy=%d, j=%d\n", hmax, y, nextVy, j)
+ }
+ }
+
+ fmt.Printf("x1=%d, x2=%d, y1=%d, y2=%d\n", x1, x2, y1, y2)
+ fmt.Printf("i=%d, x=%d, vx=%d\n", i, x, vx)
+ fmt.Println(hmax)
+}
diff --git a/2021/17/input b/2021/17/input
new file mode 100644
index 0000000..1242878
--- /dev/null
+++ b/2021/17/input
@@ -0,0 +1 @@
+target area: x=265..287, y=-103..-58
diff --git a/2021/17/second.go b/2021/17/second.go
new file mode 100644
index 0000000..49eb9cb
--- /dev/null
+++ b/2021/17/second.go
@@ -0,0 +1,54 @@
+package main
+
+import (
+ "bufio"
+ "fmt"
+ "os"
+ "strconv"
+ "strings"
+)
+
+type vector struct {
+ x, y int
+}
+
+func main() {
+ scanner := bufio.NewScanner(os.Stdin)
+ scanner.Scan()
+ line := scanner.Text()
+ elts := strings.Split(line, "..")
+ eltsx1 := strings.Split(elts[0], "=")
+ x1, _ := strconv.Atoi(eltsx1[1])
+ eltsx2 := strings.Split(elts[1], ",")
+ x2, _ := strconv.Atoi(eltsx2[0])
+ eltsy1 := strings.Split(elts[1], "=")
+ y1, _ := strconv.Atoi(eltsy1[1])
+ y2, _ := strconv.Atoi(elts[2])
+
+ possible := 0
+ for nextVx := 0; nextVx <= x2; nextVx++ {
+ out:
+ for nextVy := y1; nextVy < 1000; nextVy++ {
+ vx := nextVx
+ vy := nextVy
+ x := 0
+ y := 0
+ for {
+ if x >= x1 && x <= x2 && y >= y1 && y <= y2 {
+ possible++
+ continue out
+ }
+ if x > x2 || y < y1 {
+ break
+ }
+ if vx >= 0 {
+ x += vx
+ vx--
+ }
+ y += vy
+ vy--
+ }
+ }
+ }
+ fmt.Println(possible)
+}