bubblesortとquicksortの性能比較に関数ポインタを導入
bubblesortとquicksortを関数ポインタで扱うようにした。
これがコードの抽象度を上げるということかな。
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#include <stdio.h> #include <stdlib.h> #include <time.h> // 時間経過ナノ秒計算 int calc_timelapse_nsec(struct timespec start, struct timespec end){ if(start.tv_sec == end.tv_sec){ // 秒が同じ return end.tv_nsec - start.tv_nsec; }else{ // 秒が異なる int diff_sec = end.tv_sec - start.tv_sec; int diff_nsec = diff_sec * 1000000000; return diff_nsec + (end.tv_nsec - start.tv_nsec); } } void dispArrayList(int *a, int length){ for(int i=0; i<length; i++){ printf("[%d] : %d\n", i, a[i]); } } void dispArrayLine(int *a, int length){ for(int i=0; i<length; i++){ printf("%d", a[i]); if(i == length - 1){ printf("\n"); }else{ printf(" "); } } } void resetArray(int *a, int length){ for(int i=0; i<length; i++){ a[i] = 0; } } void init(){ srand(time(NULL)); } double getRandomDouble(){ return rand() * 1.0 / RAND_MAX; } int getRandomIntMinMax(int min, int max){ if(max < min){ return max; }else{ return min + (int)(getRandomDouble() * (max - min + 1)); } } int getRandomInt(){ int min = 0; int max = 9; return getRandomIntMinMax(min, max); } void setRandomForArray(int *a, int length){ for(int i=0; i<length; i++){ a[i] = getRandomInt(); } } void swap(int *a, int l, int r){ int t = a[l]; a[l] = a[r]; a[r] = t; } void bubblesort(int *a, int length){ for(int i=0; i<length-1; i++){ for(int j=i; j<length; j++){ if(a[j] < a[i]){ swap(a, i, j); } } } } int getPivot(int a, int b, int c){ if(b < a){ if(a < c){ return a; }else{ return b < c ? b : c; } }else{ if(b < c){ return b; }else{ return a < c ? a : c; } } } void quicksort_core(int *a, int length, int left, int right){ if(right <= left){ return; } int l = left; int r = right; int p = getPivot(a[l], a[l+1], a[r]); while(1){ while(a[l] < p){ l++; } while(p < a[r]){ r--; } if(r <= l){ break; } swap(a, l, r); l++; r--; } quicksort_core(a, length, left, l-1); quicksort_core(a, length, r+1, right); } void quicksort(int *a, int length){ int left = 0; int right = length - 1; quicksort_core(a, length, left, right); } int calcTimeLapse_sort_nsec( void (*sort)(int*, int), int *a, int length ){ int b[length]; for(int i=0; i<length; i++){ b[i] = a[i]; } struct timespec ts_start, ts_end; timespec_get(&ts_start, TIME_UTC); sort(b, length); timespec_get(&ts_end, TIME_UTC); return calc_timelapse_nsec(ts_start, ts_end); } int calcTimeLapse_sort_average_nsec( void (*sort)(int*, int), int length, int times ){ int a[length]; int sum_nsec = 0; for(int i=0; i<times; i++){ setRandomForArray(a, length); sum_nsec += calcTimeLapse_sort_nsec(sort, a, length); } return sum_nsec / times; } int main(void){ /* 準備 */ init(); /* 宣言 */ int times = 10000; int length = 30; /* 処理 */ int timelapse_bubblesort_average_nsec = calcTimeLapse_sort_average_nsec(bubblesort, length, times); int timelapse_quicksort_average_nsec = calcTimeLapse_sort_average_nsec(quicksort, length, times); /* 出力 */ printf("timelapse_bubblesort_average_nsec : %d\n", timelapse_bubblesort_average_nsec); printf("timelapse_quicksort_average_nsec : %d\n", timelapse_quicksort_average_nsec); } |
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timelapse_bubblesort_average_nsec : 1845 timelapse_quicksort_average_nsec : 1177 |
