Recursive and iterative two ways to achieve merge sort (Java edition)

Recursive version

 PackageMergeSort;ImportUtils.sortutils;/** * Merge sort recursive version * @author liguodong */ Public  class Demo02 {     Public Static void MergeSort(int[] a) {Msort (A, A,0, a.length-1); }/** * * @param SR for data to be sorted * @param TR1 for sorted data * @param S * @param /c6> T * /     Public Static void Msort(int[] SR,int[] TR1,intSintT) {intMint[] TR2 =New int[Sr.length];if(s==t)        {Tr1[s] = Sr[s]; }Else{m = (s+t)/2;//4Msort (SR, TR2, S, m); Msort (SR, TR2, m+1, t); Merge (TR2, TR1, S, M, T);//0 4 8}    }//Merge two ordered arrays    /** * @param SR has two ordered arrays * @param TR combines the two ordered arrays of SR into an array TR * @param i * @p Aram m * @param n * *     Public Static void Merge(int[] SR,int[] TR,intIintMintN) {intj,k,l;//i (0~4) J (5~8)         for(j=m+1, K=i; I<=m && j<=n; k++) {if(Sr[i]<sr[j])            {Tr[k] = sr[i++]; }Else{Tr[k] = sr[j++]; }        }if(i<=m) { for(L =0; L <= m-i;            l++) {Tr[k+l] = sr[i+l]; }        }if(j<=n) { for(L =0; L <= n-j;            l++) {Tr[k+l] = sr[j+l]; }        }    } Public Static void Main(string[] args) {int[] A = {2,3,5,4,1,6,9,8,7};        MergeSort (a);    Sortutils.printstring (a); }}

Analysis of Complexity

Iteration Version

 PackageMergeSort;ImportUtils.sortutils;/** * Recursive sort iterations * @author liguodong * */ Public  class Demo03 {     Public Static void MergeSort(int[] a) {int[] TR =New int[A.length];//For storing merge results        intk=1;//Start, sub-sequence length is 1         while(k<a.length) {Mergepass (A, TR, K, a.length);//Merge the previously unordered data 22 into the TRK =2*k;//Sub-sequence length doubledMergepass (TR, A, K, a.length);//To merge the ordered sequence of 22 merges in the TR into the array aK =2*k;//Sub-sequence length doubled}    } Public Static void Mergepass(int[] SR,int[] TR,intSintLen) {intI=0; while(I < len-2*s+1) {//8Merge (sr,tr,i,i+s-1, i+2(So1);//22 Mergei=i+2*s; }//Processing the last Mantissa        //i=8        if(i< len-s+1){//9Merge (SR, TR, I, i+s-1, len-1);//Merge the last two sequences}Else{ for(intj = i; J < Len; J + +) {//If only a single sub-sequence is left at the endTR[J] = Sr[j]; }        }       } Public Static void Merge(int[] SR,int[] TR,intIintMintN) {intj,k,l;//i (0~4) J (5~8)         for(j=m+1, K=i; I<=m && j<=n; k++) {if(Sr[i]<sr[j])            {Tr[k] = sr[i++]; }Else{Tr[k] = sr[j++]; }        }if(i<=m) { for(L =0; L <= m-i;            l++) {Tr[k+l] = sr[i+l]; }        }if(j<=n) { for(L =0; L <= n-j;            l++) {Tr[k+l] = sr[j+l]; }        }    } Public Static void Main(string[] args) {int[] A = {2,3,5,4,1,6,9,8,7,Ten, -, $, +, -, -, to, -, +, at, +, at, +, -, +};        MergeSort (a);    Sortutils.printstring (a); }}

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Recursive and iterative two ways to achieve merge sort (Java edition)