Created
June 18, 2016 18:58
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merge sort
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#include <stdio.h> | |
#include <stdint.h> | |
#include <stdlib.h> | |
#define NDATA 100000 | |
void swap(uint32_t* ); | |
uint32_t** sepaTwo(uint32_t*, uint32_t); | |
uint32_t* mergeTwo(uint32_t*, uint32_t, uint32_t*, uint32_t); | |
uint32_t* mergeSort(uint32_t*, uint32_t); | |
int main(void) { | |
FILE *f = fopen("IntegerArray.txt","r"); | |
uint32_t *data = (uint32_t*) malloc(sizeof(uint32_t)*NDATA); | |
uint32_t iArray = 0; | |
while (!feof(f) && iArray < NDATA) { | |
fscanf (f, "%d\n", &data[iArray++]); | |
} | |
for (int i=0; i<iArray; ++i) printf("%d\n", data[i]); | |
uint32_t *dataSort = mergeSort(data, iArray); | |
for (int i=0; i<iArray; ++i) printf("%d\n", dataSort[i]); | |
free(data); | |
free(dataSort); | |
fclose(f); | |
return 0; | |
} | |
void swap(uint32_t* data) { | |
uint32_t b = data[0]; | |
data[0] = data[1]; | |
data[1] = b; | |
} | |
uint32_t** sepaTwo(uint32_t* data, uint32_t size_data){ | |
uint32_t** sepData = (uint32_t**) malloc(sizeof(uint32_t*)*2); | |
sepData[0] = &data[0]; | |
sepData[1] = &data[size_data/2]; | |
return sepData; | |
} | |
uint32_t* mergeTwo(uint32_t* A, uint32_t nA, uint32_t* B, uint32_t nB){ | |
uint32_t iA = 0, iB = 0, iC = nA+nB; | |
uint32_t* data_merged = (uint32_t*) malloc(sizeof(uint32_t)*iC); | |
for (int i=0; i<iC; ++i) { | |
if ( (iB==nB) || (iA != nA && A[iA]<B[iB]) ) { | |
data_merged[i] = A[iA++]; | |
} else{ | |
data_merged[i] = B[iB++]; | |
} | |
} | |
return data_merged; | |
} | |
uint32_t* mergeSort(uint32_t* data, uint32_t size_data) { | |
uint32_t* data_sorted; | |
if (size_data <=2) { | |
data_sorted = (uint32_t*) malloc(sizeof(uint32_t)*size_data); | |
for (int i=0; i<size_data; ++i) { | |
data_sorted[i] = data[i]; | |
} | |
if (size_data == 1) { | |
return data_sorted; | |
} | |
if (size_data == 2) { | |
if (data[0] > data[1]) swap(data_sorted); | |
} | |
return data_sorted; | |
} | |
uint32_t** sepData = sepaTwo(data, size_data); | |
uint32_t* data1 = mergeSort(sepData[0], size_data/2); | |
uint32_t* data2 = mergeSort(sepData[1], (size_data+1)/2); | |
data_sorted = mergeTwo(data1, size_data/2, data2, (size_data+1)/2); | |
free(data1); | |
free(data2); | |
free(sepData); | |
return data_sorted; | |
} |
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