package algo

func DP(t1 []int, t2 []int, e1 []int, e2 []int) int {
	Len := len(t1)
	if len(t2) != Len || len(e1) != Len || len(e2) != Len {
		return -1
	}
	dp1 := make([]int, Len)
	dp2 := make([]int, Len)
	dp1[0], dp2[0] = t1[0], t2[0]

	for i := 1; i < Len; i++ {
		dp1[i] = min(dp1[i-1], dp2[i-1]+e2[i-1]) + t1[i]
		dp2[i] = min(dp2[i-1], dp1[i-1]+e1[i-1]) + t2[i]
	}

	return min(dp1[Len-1], dp2[Len-1])
}

func Rec(t1 []int, t2 []int, e1 []int, e2 []int) int {
	Len := len(t1)
	if len(t2) != Len || len(e1) != Len || len(e2) != Len {
		return -1
	}

	return min(rec(t1, t2, e1, e2))
}

func rec(t1 []int, t2 []int, e1 []int, e2 []int) (int, int, int, int) {
	Len := len(t1)
	if Len == 1 {
		return t1[0], 0x3f3f3f3f3f3f3f3f, 0x3f3f3f3f3f3f3f3f, t2[0]
	}
	mid := Len / 2
	a11, a12, a21, a22 := rec(t1[:mid], t2[:mid], e1[:mid], e2[:mid])
	b11, b12, b21, b22 := rec(t1[mid:], t2[mid:], e1[mid:], e2[mid:])
	s1 := e1[mid-1]
	s2 := e2[mid-1]
	return min(a11+b11, a11+s1+b21, a12+s2+b11, a12+b21), min(a11+b12, a11+s1+b22, a12+s2+b12, a12+b22),
		min(a21+b11, a21+s1+b21, a22+b21, a22+s2+b11), min(a21+b12, a21+s1+b22, a22+b22, a22+s2+b12)
}