Given an array of integers and an integer k, find out whether there there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between iand j is at most k.
方法1：暴力解法
代码如下：
public class Solution {
public boolean containsNearbyDuplicate(int[] nums, int k) {
int len=nums.length;
for(int i=0;i<len;i++){
for(int tmp=1;tmp<=k && i+tmp<len;tmp++)
if(nums[i]==nums[i+tmp])
return true;
}
return false;
}
}
运行超时：
方法2：分析：
代码如下：
public class Solution {
public boolean containsNearbyDuplicate(int[] nums, int k) {
Set<Integer> set = new HashSet<Integer>();
int start = 0, end = 0;
for(int i = 0; i < nums.length; i++){
if(!set.contains(nums[i])){
set.add(nums[i]);
end++;
} else
return true;
if(end - start > k) {
set.remove(nums[start]);
start++;
}
}
return false;
}
}
运行结果：
