merge_sort

/*
 * File:   main.c
 * Author: Gerardo Cicalese
 *
 * Created on 16 settembre 2019, 15.48
 */

#include <stdio.h>
#include <stdlib.h>

void print_vex(int * vex, int len){
    if(len<1)
        return;
    printf("%d ", *vex);
    print_vex(vex+1, len-1);
}

void copy_vex(int * a, int * b, int len){
    if(len==0)
        return;
    *b=*a;
    copy_vex(a+1, b+1, len-1);
}

void merge(int * a, int lena, int * b, int lenb, int * temp){
    if(lena>0&&lenb>0)
        if(*a<*b){
            *temp=*a;
            merge(a+1, lena-1, b, lenb, temp+1);
        }
        else{
            *temp=*b;
            merge(a, lena, b+1, lenb-1, temp+1);
        }
    else{
        if(lena==0&&lenb>0){
            *temp=*b;
            merge(a, lena, b+1, lenb-1, temp+1);
        }
        else if(lena>0&&lenb==0){
            *temp=*a;
            merge(a+1, lena-1, b, lenb, temp+1);
        }
    }
}

void merge_sort(int * array, int len, int * temp){
    if( len < 2 )
        return;

    int pivot=len/2;

    merge_sort(array, pivot, temp);
    merge_sort(array+pivot, len-pivot, temp);

    merge(array, pivot, array+pivot, len-pivot, temp);
    copy_vex(temp, array, len);
}

int main(void){
    int array[10]={23, 62, 15, 97, 35, 78, 34, 89, 13, 57}, temp[10];
    merge_sort(array, 10, temp);
    print_vex(array, 10);
    return 0;
}