add 1797

fishercoder1534 · fishercoder1534 · commit bacd984b0362 · 2021-03-20T11:51:47.000-07:00
diff --git a/README.md b/README.md
@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ &#9733;
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
+|1797|[Design Authentication Manager](https://leetcode.com/problems/design-authentication-manager/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1797.java) ||Medium|HashTable, Design|
 |1796|[Second Largest Digit in a String](https://leetcode.com/problems/second-largest-digit-in-a-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1796.java) ||Easy|String|
 |1792|[Maximum Average Pass Ratio](https://leetcode.com/problems/maximum-average-pass-ratio/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1792.java) ||Medium|Heap|
 |1791|[Find Center of Star Graph](https://leetcode.com/problems/find-center-of-star-graph/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1791.java) ||Medium|Graph|
diff --git a/src/main/java/com/fishercoder/solutions/_1797.java b/src/main/java/com/fishercoder/solutions/_1797.java
@@ -0,0 +1,45 @@
+package com.fishercoder.solutions;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class _1797 {
+    public static class Solution1 {
+        public static class AuthenticationManager {
+
+            int timeToLive;
+            int currentTime;
+            Map<String, Integer> map;//tokenId -> expireTime
+
+            public AuthenticationManager(int timeToLive) {
+                this.timeToLive = timeToLive;
+                this.currentTime = 0;
+                this.map = new HashMap<>();
+            }
+
+            public void generate(String tokenId, int currentTime) {
+                map.put(tokenId, currentTime + timeToLive);
+            }
+
+            public void renew(String tokenId, int currentTime) {
+                Integer expireTime = map.getOrDefault(tokenId, -1);
+                if (expireTime == -1 || expireTime <= currentTime) {
+                    return;
+                }
+                map.put(tokenId, currentTime + timeToLive);
+            }
+
+            public int countUnexpiredTokens(int currentTime) {
+                Map<String, Integer> tmp = new HashMap<>();
+                for (String token : map.keySet()) {
+                    if (map.get(token) > currentTime) {
+                        tmp.put(token, map.get(token));
+                    }
+                }
+                map.clear();
+                map.putAll(tmp);
+                return map.size();
+            }
+        }
+    }
+}
