package q399

func calcEquation(equations [][]string, values []float64, queries [][]string) []float64 {
	seen := make(map[[2]string]float64, len(equations)*8)
	queue := make([][2]string, 0, len(equations)*8)

	for i := range equations {
		eq, val := equations[i], values[i]
		eq1, eq2 := [2]string{eq[0], eq[1]}, [2]string{eq[1], eq[0]}
		seen[eq1] = val
		seen[eq2] = 1 / val
		queue = append(queue, eq1, eq2)

		seen[[2]string{eq[0], eq[0]}] = 1
		seen[[2]string{eq[1], eq[1]}] = 1
	}

	for ; len(queue) > 0; queue = queue[1:] {
		eq := queue[0]
		val := seen[eq]

		for i := range equations {
			var newVar string
			newVal := val
			switch eq[0] {
			case equations[i][0]:
				newVar = equations[i][1]
				newVal *= 1 / values[i]
			case equations[i][1]:
				newVar = equations[i][0]
				newVal *= values[i]
			default:
				continue
			}

			newEq1 := [2]string{newVar, eq[1]}
			if _, ok := seen[newEq1]; !ok {
				seen[newEq1] = newVal
				queue = append(queue, newEq1)
			}
			newEq2 := [2]string{eq[1], newVar}
			if _, ok := seen[newEq2]; !ok {
				seen[newEq2] = 1 / newVal
				queue = append(queue, newEq2)
			}
		}
	}

	ret := make([]float64, len(queries))
	for i := range queries {
		if val, ok := seen[[2]string{queries[i][0], queries[i][1]}]; ok {
			ret[i] = val
		} else {
			ret[i] = -1
		}
	}
	return ret
}

var _ = calcEquation