Add Solution.java to problems 0690

Author: huaxu1024

solution/0690. Employee Importance/README_EN.md

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+# Employee Importance
+
+You are given a data structure of employee information, which includes the employee's unique id, his importance value and his direct subordinates' id.
+
+For example, employee 1 is the leader of employee 2, and employee 2 is the leader of employee 3. They have importance value 15, 10 and 5, respectively. Then employee 1 has a data structure like [1, 15, [2]], and employee 2 has [2, 10, [3]], and employee 3 has [3, 5, []]. Note that although employee 3 is also a subordinate of employee 1, the relationship is not direct.
+
+Now given the employee information of a company, and an employee id, you need to return the total importance value of this employee and all his subordinates.
+
+
+## Example 1:
+```text
+Input: [[1, 5, [2, 3]], [2, 3, []], [3, 3, []]], 1
+
+Output: 11
+
+Explanation: Employee 1 has importance value 5, and he has two direct subordinates: employee 2 and employee 3. They both have importance value 3. So the total importance value of employee 1 is 5 + 3 + 3 = 11.
+```
+## Note:
+
+- One employee has at most one direct leader and may have several subordinates.
+- The maximum number of employees won't exceed 2000.

solution/0690. Employee Importance/Solution.java

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+/*
+// Employee info
+class Employee {
+    // It's the unique id of each node;
+    // unique id of this employee
+    public int id;
+    // the importance value of this employee
+    public int importance;
+    // the id of direct subordinates
+    public List<Integer> subordinates;
+};
+*/
+
+import java.util.*;
+
+class Solution {
+	public int getImportance(List<Employee> employees, int id) {
+		Map<Integer, Employee> map = new HashMap<>();
+		for (Employee employee : employees) {
+			map.put(employee.id, employee);
+		}
+		return dfs(map, id);
+	}
+
+	private int dfs(Map<Integer, Employee> map, int id) {
+		Employee employee = map.get(id);
+		int ans = employee.importance;
+		for (Integer subordinate : employee.subordinates) {
+			ans += dfs(map, subordinate);
+		}
+		return ans;
+	}
+}