[Leetcode] Largest number, problem solving report

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Given a list of non negative integers, arrange them such that they form the largest number.

For example, given [3, 5, 9], and the largest formed number is 9534330.

Note:the result May is very large, so you need to return a string instead of an integer.

Ideas

The idea is clear: convert the int num array to a string num array, and then sort it. The rules for sorting are as follows:

For example strings str1 and str2, stitching strings CMP1 = str1 + str2,cmp2 = str2 + str1. Sort by dictionary, if CMP1 > cmp2, then str1 > str2. Conversely, then str1 < str2.
Note: You can use the comparator interface provided by Java, and then implement the dictionary in reverse order.

Cpmparator interface use can refer to my blog: comparator and comparable use the difference.

AC Code

The AC code is as follows:

 Public  class solution {     Public StaticStringLargestnumber(int[] num) {StringBuilder res =NewStringBuilder (); string[] Numarrays =NewString[num.length];intZeronum =0; for(inti =0; i < num.length; i + +) {if(Num[i] = =0) {zeronum + +;        } Numarrays[i] = integer.tostring (Num[i]); }if(Zeronum = = num.length) {return "0"; } arrays.sort (Numarrays,NewNumcomparator ()); for(String s:numarrays)        {Res.append (s); }returnRes.tostring (); }Private Static  class numcomparator implements Comparator<String> {        @Override         Public int Compare(String str1, String str2)            {String CMP1 = str1 + str2; String CMP2 = str2 + str1;returnCmp1.compareto (CMP2) *-1; }    }}

[Leetcode] Largest number, problem solving report