排序算法01：選擇排序

選擇排序（SelectionSort）的時間複雜度O(N2)

#include "SelectionSort.h"
#include "Print.h"

// 選擇排序，時間複雜度爲O(N2)
void SelectionSort(int A[], int N)
{
	int i, j, temp;
	for(i = 0; i < N; i++)
	{
		for(j = i + 1; j < N; j++) // 每次循環將第一個位置的數與後面的數進行比較，替換的結果最終是把最小的數放置到最前面
		{
			if(A[i] > A[j])	
			{
				temp = A[i];
				A[i] = A[j];
				A[j] = temp;
			}
			//printf("(%i, %d) ", i, j);
			//Print(A, N);
		}
	}
}

 

主程序main.cpp

#include "InsertionSort.h"
#include "SelectionSort.h"
#include "ShellSort.h"
#include "MergeSort.h"
#include "HeapSort.h"
#include "Print.h"
#include <time.h>

#define N 10000

int main()
{
	int A[10] = {9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
	int B[N];
	FILE *fp = fopen("data.txt", "r");
	for(int i = 0; i < N; i++)
	{
		fscanf(fp, "%d", &B[i]);
	}
	
	clock_t start = clock();	// 計時開始

	// 插入排序Time = 327ms
	//InsertionSort(B, 10000);

	// 選擇排序Time = 967ms
	SelectionSort(B, 10000);

	// 希爾排序Time = 10ms
	//ShellSort(B, 10000);

	// 歸併排序Time = 27ms
	//MergeSort(B, N, 0, N - 1);

	// 堆排序Time = 4694ms
	//HeapSort(B, N);

	clock_t stop = clock();		// 計時結束
	
	//Print(B, N);
	
	printf("Time = %dms\n", (stop - start));
	//Print(B, N);

	return 0;
}

耗時 Time = 967ms。