minmax.cpp

常用算法与数据结构原代码

// find min and max of n elements
// non-recursive divide-and-conquer version

#include <iostream.h>

template<class T>
bool MinMax(T w[], int n, T& Min, T& Max)
{// Locate min and max of w[0:n-1].
	// Return false if fewer than one element.
	// special cases, n <= 1
	if (n < 1) 
		return false;
	if (n == 1) 
	{
		Min = Max = 0; 
		return true;
	}
	
	// initialize Min and Max
	int s;  // start point for loop
	if (n % 2) 
	{// n is odd
		Min = Max = 0;
		s = 1;
	}
	else 
	{// n is even, compare first pair
		if (w[0] > w[1]) 
		{
            Min = 1;
            Max = 0;
		}
		else 
		{
			Min = 0;
			Max = 1;}
			s = 2;
	}
	
	// compare remaining pairs
	for (int i = s; i < n; i += 2) 
	{
		// find larger of w[i] and w[i+1]
		// then compare larger with w[Max]
		// and smaller with w[Min]
		if (w[i] > w[i+1]) 
		{
			if (w[i] > w[Max]) 
				Max = i;
			if (w[i+1] < w[Min]) 
				Min = i + 1;}
		else 
		{
			if (w[i+1] > w[Max]) 
				Max = i + 1;
			if (w[i] < w[Min])
				Min = i;
		}
	}
	
	return true;
}

void main(void)
{
	int w[12] = {10, 25, 8, 2, 8, 10, 6, 3, 1, 20, 4, 35};
	int n = 12;
	int Min, Max;
	MinMax(w,n,Min,Max);
	cout << w[Min] << ' ' << w[Max] << endl;
}