Algorithm-Key Index counting method

The key index counting method is suitable for the integer divided into the smaller simple sorting method, the basic step is divided into four steps:

1. Statistics on the number of occurrences of each classification;

2. Convert the number of classifications to the corresponding index;

3. Sort the original array by the weight of the category in the middle array;

4. Assign the intermediate array after sorting to the original array;

Basic Definition

First, you define the required classes for sorting:

@interface keyindexmodel:nsobject@property  (assign,nonatomic)  nsinteger  key; @property  (Strong, nonatomic)  nsstring  *value;-(instancetype) Initwithkeyvalue: (Nsinteger) Key  value: (NSString *) value;@ End@interface keyindexsort:nsobject-(void) Sort: (Nsmutablearray *) DataSource Categorynumber: (nsinteger) number; @end

To implement a specific sorting method:

-(void) Sort: (Nsmutablearray *) DataSource Categorynumber: (nsinteger) number{Nsinteger len=[datasource Count];    Nsmutablearray *temparr=[[nsmutablearray Alloc]initwithcapacity:1];    Http://www.cnblogs.com/xiaofeixiang/for (Nsinteger i=0; i<len; i++) {[Temparr addobject:[nsnull null]];    } Nsmutablearray *count=[[nsmutablearray alloc]initwithcapacity:1];    for (Nsinteger i=0; i<number+1; i++) {[Count Addobject:[nsnumber numberwithinteger:0]];        }//Count the number of times per classification for (Nsinteger i=0;i<len; i++) {Keyindexmodel *model=datasource[i];    Count[model.key+1]=[nsnumber numberwithinteger:[count[model.key+1] integervalue]+1]; }//To convert the number of occurrences to an index, the first group 3 times, the second group 5 times, so that the index corresponding to the third group starting is 8 for (Nsinteger j=0; j<number; J + +) {Count[j+1]=[nsnumber n    UMBERWITHINTEGER:[COUNT[J] integervalue]+[count[j+1] integervalue];        }//To classify elements from top to bottom for (Nsinteger m=0; m<len; m++) {Keyindexmodel *model=datasource[m]; temparr[[count[Model.key] Integervalue]]=model;    Count[model.key]=[nsnumber Numberwithinteger:[count[model.key] integervalue]+1];    }//Reorder assignment for (Nsinteger i=0; i<len; i++) {datasource[i]=temparr[i]; }    }

sort test

        Nsmutablearray *datasource=[[nsmutablearray Alloc]initwithcapacity:1];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:0 value:@ "Flyelephant"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:1 value:@ "Keso"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:2 value:@ "Sananoro"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:3 value:@ "http://www.cnblogs.com/xiaofeixiang/"]];                [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:3 value:@ "ios technology: 228407086"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:2 value:@ "Beijing"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:1 value:@ "Shanghai"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:3 value:@ "Shenzhen"]];        [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:2 value:@ "Guangzhou"]]; [DataSource addobject: [[Keyindexmodel alloc]initwithkeyvalue:0 value:@ "Henan"];        Keyindexsort *indexsort=[[keyindexsort Alloc]init];         [Indexsort Sort:datasource Categorynumber:5]; [DataSource enumerateobjectsusingblock:^ (id _nonnull obj, nsuinteger idx, BOOL * _nonnull stop)             {Keyindexmodel *model=obj;         NSLog (@ "%ld--%@", Idx,model.value); }];

Sort Result:

Algorithm-Key Index counting method