[Easy] Title: 228. Summary Ranges - LeetCode

Author: JinHyung-dev

LeetCode/Easy/228. Summary Ranges/README.md

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+# [Easy] Summary Ranges
+
+[문제 링크](https://leetcode.com/problems/summary-ranges/)
+
+### 문제 설명
+
+You are given asorted uniqueinteger array`nums`.
+
+Arange`[a,b]`is the set of all integers from`a`to`b`(inclusive).
+
+Return*thesmallest sortedlist of ranges thatcover all the numbers in the array exactly*. That is, each element of`nums`is covered by exactly one of the ranges, and there is no integer`x`such that`x`is in one of the ranges but not in`nums`.
+
+Each range`[a,b]`in the list should be output as:
+
+- `"a->b"`if`a != b`
+- `"a"`if`a == b`
+
+Example 1:
+
+```
+Input: nums = [0,1,2,4,5,7]
+Output: ["0->2","4->5","7"]
+```
+
+Explanation: The ranges are:
+[0,2] --> "0->2"
+[4,5] --> "4->5"
+[7,7] --> "7"
+
+Example 2:
+
+```
+Input: nums = [0,2,3,4,6,8,9]
+Output: ["0","2->4","6","8->9"]
+```
+
+Explanation: The ranges are:
+[0,0] --> "0"
+[2,4] --> "2->4"
+[6,6] --> "6"
+[8,9] --> "8->9"
+
+Constraints:
+
+- `0 <= nums.length <= 20`
+- `231 <= nums[i] <= 231 - 1`
+- All the values of`nums`areunique.
+- `nums`is sorted in ascending order.

LeetCode/Easy/228. Summary Ranges/Summary Ranges.java

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+class Solution {
+    public List<String> summaryRanges(int[] nums) {
+        List<String> result = new ArrayList<>();
+        int start = 0;
+
+        for(int i = 1; i < nums.length; i++) {
+            if(nums[i - 1] + 1 != nums[i]) { // 이전값과 현재값이 같지 않으면(연속x면 저장)
+                if(start == i - 1) { // 시작인덱스밖에 없을 때 저장
+                    result.add(String.valueOf(nums[start]));
+                } else { // 연속 범위 저장
+                    result.add(nums[start] + "->" + nums[i-1]);
+                }
+                // 저장 후 시작값 초기화
+                start = i;
+            }
+        }
+        // 마지막 시작값 추가 계산
+        if(start == nums.length - 1) { // 남은 시작값이 마지막 인덱스일 때
+            result.add(String.valueOf(nums[start]));
+        } else {
+            result.add(nums[start] + "->" + nums[nums.length-1]);
+        }
+        return result;
+    }
+}