重拾编程之路--leetcode(java)-排序数组范围

<span style="color:#cc0000;">特别提醒：在没有确定对象是否为NULL的情况下，调用对象的函数是错误的。</span>

<span style="color:#cc0000;">           应该改为：if(nums==null)判断后才能使用</span>

</pre><pre>

import java.util.ArrayList;
import java.util.List;

public class C_sumaryRanges{
public List sumaryRanges(int []nums){
if(nums==null){
return null;
}

List<String> list=new ArrayList<>();
int begin=0;
int end=0;
int len=nums.length;
while(end<len){
if(end+1<len && nums[end+1]==nums[end]+1){
end++;
}
else{
if(begin==end){
list.add(Integer.toString(nums[end]));

}else{
list.add(Integer.toString(nums[begin])+"->"+Integer.toString(nums[end]));
}
end=end+1;
begin=end;
}

}
return list;

}

public static void main(String args[]){
C_sumaryRanges cRanges=new C_sumaryRanges();
int nums[]={0,1,2,4,5,7};
int i=0;
List<String> list=cRanges.sumaryRanges(nums);
while(i<list.size()){
System.out.print(list.get(i));
i++;
}
}

}