solve2.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
static inline int MIN(int a, int b)
{
	return a < b ? a : b;
}
static inline int MAX(int a, int b)
{
	return a > b ? a : b;
}
int maxProfit(int *a, int n)
{
	int max = a[n - 1];
	int profit = 0;
	for (int i = n - 2; i >= 0; --i) {
		max = MAX(max, a[i]);
		profit = MAX(profit, max - a[i]);
	}
	return profit;
}
/*
int maxProfit(int *a, int n)
{
	int min = a[0];
	int max = 0;
	for (int i = 1; i < n; ++i) {
		min = MIN(min, a[i]);
		max = MAX(max, a[i] - min);
	}
	return max;
}
*/
int main(int argc, char **argv)
{
	int a[20], n;
	while (scanf("%d", &n) != EOF) {
		for (int i = 0; i < n; ++i)
			scanf("%d", a + i);
		printf("maxProfit = %d\n", maxProfit(a, n));
	}
	return 0;
}