Contains Duplicate

Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least
twice in the array, and it should return false if every element is distinct.

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/*这么写超时

public class Solution {

public boolean containsDuplicate(int[] nums) {

for(int i=0;i<nums.length-1;i++){

for(int j=i+1;j<nums.length;j++){

if(nums[i]==nums[j]){

return true;

}

}

}

return false;

}

}

**/

========================正确的写法==================

算法题首先要考虑到边界问题的处理、这类问题首先考虑是否需要排序，如果可以排序问题处理起来就简单多了 ！

public class Solution {

public boolean containsDuplicate(int[] nums) {

if(nums.length<=0){

return false;

}

Arrays.sort(nums);

for(int i=0;i<nums.length-1;i++){

if(nums[i]==nums[i+1]){

return true;

}

}

return false;

}}