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MergeSort.c
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MergeSort.c
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//********************************************************************
// Author: Xiayf
// Date: 2011/9/29
// What: Merge Sort
//********************************************************************
#include <stdio.h>
#include <stdlib.h>
void mergeSort(int *arrayToBeSorted, int start, int end);
void merge(int *arrayToBeSorted, int start, int middle, int end);
int main()
{
int volume, index, data;
printf("Please Input the Volume of Array to be Sorted:");
scanf("%d",&volume);
int arrayToBeSorted[volume];
for(index = 0; index < volume; index++){
scanf("%d",&data);
arrayToBeSorted[index] = data;
}
mergeSort(arrayToBeSorted, 0, volume - 1);
for(index = 0; index < volume; index ++){
printf("%d\n", arrayToBeSorted[index]);
}
return 0;
}
void mergeSort(int *arrayToBeSorted, int start, int end){
int middle;
if(start < end){
middle = (start + end) / 2;
mergeSort(arrayToBeSorted, start, middle);
mergeSort(arrayToBeSorted, middle + 1, end);
merge(arrayToBeSorted, start, middle, end);
}
}
void merge(int *arrayToBeSorted, int start, int middle, int end){
int lenOfLeft, lenOfRight;
lenOfLeft = middle - start + 1;
lenOfRight = end - middle;
int leftArray[lenOfLeft], rightArray[lenOfRight], index;
for(index = 0; index < lenOfLeft; index ++)
leftArray[index] = arrayToBeSorted[start + index];
for(index = 0; index < lenOfRight; index ++)
rightArray[index] = arrayToBeSorted[middle + index + 1];
int leftIndex = 0, rightIndex = 0;
for(index = start; index <= end; index ++){
if(leftIndex == lenOfLeft){
arrayToBeSorted[index] = rightArray[rightIndex];
rightIndex++;
}else if(rightIndex == lenOfRight){
arrayToBeSorted[index] = leftArray[leftIndex];
leftIndex++;
}else if(leftArray[leftIndex] <= rightArray[rightIndex]){
arrayToBeSorted[index] = leftArray[leftIndex];
leftIndex++;
}else{
arrayToBeSorted[index] = rightArray[rightIndex];
rightIndex ++;
}
}
}