2174.cpp

这是哈尔滨工业大学acmOJ的源代码

/*  This Code is Submitted by wywcgs for Problem 2174 on 2006-03-21 at 13:50:25 */ 
#include <cstdio>
#include <algorithm>
using namespace std;

const int MAX = 5120;

int main()
{
	int blank[MAX], n, i;
	
	while(scanf("%d", &n) != EOF && n != 0) {
		int used = 0, m; blank[0] = 0;
		for(m = i = 0; i < n; i++) {
			int post; scanf("%d", &post);
			if(post == 1) blank[++m] = 0;
			else blank[m]++;
		}
		if(m != 0) blank[0] += blank[m--];
		else { used++; blank[0]--; }
		for(i = 0; i <= m; i++) used += blank[i] / 2;
		printf("%d\n", used);
	}
	
	return 0;
}