|526|[Beautiful Arrangement](https://leetcode.com/problems/beautiful-arrangement/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_526.java) | O(n) |O(h) | Medium | Backtracking

|525|[Contiguous Array](https://leetcode.com/problems/contiguous-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_525.java) | O(n) |O(n) | Medium | HashMap

|524|[Longest Word in Dictionary through Deleting](https://leetcode.com/problems/longest-word-in-dictionary-through-deleting/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_524.java) | O(n) |O(n) | Medium | Sort

|523|[Continuous Subarray Sum](https://leetcode.com/problems/continuous-subarray-sum/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_523.java)| O(n^2)|O(n)| Medium|

|523|[Continuous Subarray Sum](https://leetcode.com/problems/continuous-subarray-sum/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_523.java) | O(n) |O(1) | Medium| DP

|522|[Longest Uncommon Subsequence II](https://leetcode.com/problems/longest-uncommon-subsequence-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_522.java)| O(x*n^2) (x is average length of strings)|O(1)| Medium|

|521|[Longest Uncommon Subsequence I](https://leetcode.com/problems/longest-uncommon-subsequence-i/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_521.java)| O(max(x,y)) (x and y are length of strings)|O(1)| Easy|

|520|[Detect Capital](https://leetcode.com/problems/detect-capital/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_520.java)| O(n)|O(1)| Easy|

packagecom.fishercoder.solutions;

importjava.util.HashMap;

importjava.util.Map;

publicclass_523 {

publicbooleancheckSubarraySumOnTimeO1Space(int[]nums,intk) {

Map<Integer,Integer>map =newHashMap<>();

map.put(0, -1);

intsum =0;

for (inti =0;i <nums.length;i++) {

sum +=nums[i];

if (k !=0) {

sum %=k;

}

Integerprev =map.get(sum);

if (prev !=null) {

if (i -prev >1) {

returntrue;

}

}else {

map.put(sum,i);

}

}

returnfalse;

}

publicbooleancheckSubarraySum(int[]nums,intk) {

if (nums ==null ||nums.length ==0)returnfalse;