add new solutions

solutions/3/q399/solution.go

@@ -0,0 +1,60 @@
+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