二路归并

#include "stdafx.h"#include <iostream>//合并void MERGE(int a[],size_t beg,size_t mid,size_t en){size_t lenl=mid-beg+1;size_t lenr=en-mid;int* L=(int*)malloc(sizeof(int)*lenl);int* R=(int*)malloc(sizeof(int)*lenr);int i=0,j=beg;while(i<lenl) L[i++]=a[j++];i=0,j=mid+1;while(i<lenr) R[i++]=a[j++];i=j=0;int k=beg;while(i<lenl&&j<lenr){if (L[i]<=R[j])a[k++]=L[i++];else a[k++]=R[j++];}while(i<lenl) a[k++]=L[i++];while(j<lenr) a[k++]=R[j++];}void MERGESort(int a[],size_t beg,size_t en){if (beg<en) {size_t mid=(beg+en)/2;MERGESort(a,beg,mid);MERGESort(a,mid+1,en);MERGE(a,beg,mid,en);}}