pat1040：有几个PAT

https://www.patest.cn/contests/pat-b-practise/1040

#include "stdio.h"

int main()
{
	int p = 0, a = 0, t = 0;
	char c;
	while(scanf("%c", &c) && ('\n' != c))
	{
		if('P' == c)
			++p;
		else if('A' == c)
			a += p;
		else if('T' == c)
			t = (t + a) % 1000000007;
	}
	printf("%d\n", t);

	return 0;
}