[Round B] China New Grad Test 2014: Problem E. Ignore all my comments

【转载请注明出处: http://blog.csdn.net/lzl124631x】

OJ: https://code.google.com/codejam/contest/2929486/dashboard#s=p4

思路:

按行为单位输入.
设置level标志指示当前在注释的第几层中, 初始为0.
普通文本状态(level == 0)下正常读入, 当遇到"/*"时level++.
注释状态(level > 0)下跳过输入, 当遇到"/*"时level++, 遇到"*/"时level--.
仅在level == 0的行尾输出'\n'.

代码:

#include <stdio.h>
#define MAX_SIZE 100000
#define COMMENT_START(s) (*(s) == '/' && *((s) + 1) == '*')
#define COMMENT_END(s) (*(s) == '*' && *((s) + 1) == '/')

int main(){
	char str_in[MAX_SIZE] = {0};
	char str_out[MAX_SIZE] = {0};
	char *p_in, *p_out;
	int level;
	freopen("E-large-practice.in","r",stdin);
	freopen("out.txt","w",stdout);
	level = 0;
	p_out = str_out;
	while(gets(str_in)){
		p_in = str_in;// new line
		while(*p_in){
			if(level == 0){// text mode
				while(*p_in && !COMMENT_START(p_in)){
					*p_out++ = *p_in++;
				}
				if(*p_in){
					p_in += 2; level++;
				}
			}else{// comment mode
				while(*p_in && !COMMENT_START(p_in) && !COMMENT_END(p_in)) p_in++;
				if(COMMENT_START(p_in)){
					p_in += 2; level++;
				}else if(COMMENT_END(p_in)){
					p_in += 2; level--;
				}
			}
		}
		if(level == 0) *p_out++ = '\n';// output '\n' at end of line in text mode
	}
	*p_out = 0;
	printf("Case #1:\n%s", str_out);
	return 0;
}