You are given an array of variable pairs equations
and an array of real numbers values
, where equations[i] = [Ai, Bi]
and values[i]
represent the equation Ai / Bi = values[i]
. Each Ai
or Bi
is a string that represents a single variable.
You are also given some queries
, where queries[j] = [Cj, Dj]
represents the jth
query where you must find the answer for Cj / Dj = ?
.
Return the answers to all queries. If a single answer cannot be determined, return -1.0
.
Note: The input is always valid. You may assume that evaluating the queries will not result in division by zero and that there is no contradiction.
Example 1:
Input: equations = [["a","b"],["b","c"]], values = [2.0,3.0], queries = [["a","c"],["b","a"],["a","e"],["a","a"],["x","x"]] Output: [6.00000,0.50000,-1.00000,1.00000,-1.00000] Explanation: Given: a / b = 2.0, b / c = 3.0 queries are: a / c = ?, b / a = ?, a / e = ?, a / a = ?, x / x = ? return: [6.0, 0.5, -1.0, 1.0, -1.0 ]
Example 2:
Input: equations = [["a","b"],["b","c"],["bc","cd"]], values = [1.5,2.5,5.0], queries = [["a","c"],["c","b"],["bc","cd"],["cd","bc"]] Output: [3.75000,0.40000,5.00000,0.20000]
Example 3:
Input: equations = [["a","b"]], values = [0.5], queries = [["a","b"],["b","a"],["a","c"],["x","y"]] Output: [0.50000,2.00000,-1.00000,-1.00000]
Constraints:
1 <= equations.length <= 20
equations[i].length == 2
1 <= Ai.length, Bi.length <= 5
values.length == equations.length
0.0 < values[i] <= 20.0
1 <= queries.length <= 20
queries[i].length == 2
1 <= Cj.length, Dj.length <= 5
-
Ai, Bi, Cj, Dj
consist of lower case English letters and digits.
class Solution { public double[] calcEquation(List<List<String>> equations, double[] values, List<List<String>> queries) { Map<String,Map<String,Double>> map = new HashMap(); for(int i=0;i<values.length;i++){ String first = equations.get(i).get(0),second = equations.get(i).get(1); map.put(first,map.getOrDefault(first,new HashMap())); map.put(second,map.getOrDefault(second,new HashMap())); Map<String,Double> firstMap = map.get(first); Map<String,Double> secondMap = map.get(second); firstMap.put(first,1d); secondMap.put(second,1d); firstMap.put(second,values[i]); secondMap.put(first,1/values[i]); } for(String key:map.keySet()){ Map<String,Double> currmap = map.get(key); for(String key1:currmap.keySet()){ for(String key2:currmap.keySet()){ if(key.equals(key1) || key.equals(key2) || key1.equals(key2)) continue; double value12 = map.get(key1).get(key)/map.get(key2).get(key); map.get(key1).put(key2,value12); map.get(key2).put(key1,1/value12); } } } double[] results = new double[queries.size()]; for(int i=0;i<queries.size();i++){ String first = queries.get(i).get(0),second = queries.get(i).get(1); if(map.get(first)!=null && map.get(first).get(second)!=null) results[i]=map.get(first).get(second); else results[i]=-1; } return results; } }