"longest-consecutive-sequence 문제"

Author: ymir0804

longest-consecutive-sequence/ymir0804.java

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+import java.util.Collections;
+import java.util.HashSet;
+
+/*
+
+*/
+class ymir0804 {
+    public int longestConsecutive(int[] nums) {
+        HashSet<Integer> numsSet = new HashSet<>();
+        int maxNum = 0;
+        for (int num: nums) {
+            numsSet.add(num);
+        }
+
+        if(numsSet.isEmpty()) {
+            return 1;
+        } else if (numsSet.size() == 1) {
+            return 0;
+        }
+
+        for (int num: numsSet) {
+            boolean isStartPoint = !numsSet.contains(num - 1);
+            if (isStartPoint) {
+                int current = num;
+                int length = 1;
+                while(numsSet.contains(++current)) {
+                    length++;
+                }
+                if(length > maxNum) {
+                    maxNum = length;
+                }
+            }
+        }
+        return maxNum;
+        }
+    }