HDU 2577 how to type

简单动态规划，用两个数组分别保存开灯与不开灯状态，该设置很重要，做题之前要考虑全面。

用两个a,b数组分别记录Caps Lock开与关时打印第i个字母的最少操作步骤;
而对于第i个字母的大小写还要分开讨论:
Ch[i]为小写: a[i]=min(a[i-1]+1,b[i-1]+2);不开灯直接字母,开灯则先关灯再按字母,最后保持不开灯; b[i]=min(a[i-1]+2,b[i-1]+2);不开灯则先按字母再开灯,开灯则Shift+字母(比关灯,按字母再开灯节省步数),最后保持开灯;
Ch[i]为大写: a[i]=min(a[i-1]+2,b[i-1]+2); b[i]=min(a[i-1]+2,b[i-1]+1)

最后,b[len-1]++,关灯嘛O(∩_∩)O~

#include <iostream>
#include <string.h>
using namespace std;

const int N = 101;
char str[N];
int a[N], b[N];//a关灯，b开灯
int min(int a, int b)
{
	if(a>b)
		return b;
	else
		return a;
}
int main()
{
	int t;
	cin >> t;
	while(t--)
	{
		memset(str, 0, sizeof(str));
		memset(a, 0, sizeof(a));
		memset(b, 0, sizeof(b));
		cin >> str;
		if(isupper(str[0]))
			a[0] = 2, b[0] = 2;
		else
			a[0] = 1, b[0] = 2;
		int n = strlen(str);
		if(str[0])
		for(int i = 1; i < n;  i ++)
		{
			if(isupper(str[i]))
			{
				a[i] = min(a[i-1] +2, b[i-1] + 2);
				b[i] = min(a[i-1] +2, b[i-1] + 1);
			}
			else
			{
				a[i] = min(a[i-1] + 1, b[i-1] +2);
				b[i] = min(a[i-1] + 2, b[i-1] +2);
			}
		}
		b[n-1]++;
		cout << min(a[n-1], b[n-1]) << endl;
	}
	return 0;
}