BL11. 实现一个HTML语法检查器
描述
实现一个HTML语法检查器。HTML语法规则简化如下：标签必须闭合，可以由开始和结束两个标签闭合，如<div></div>，也可以自闭合，输入描述
一行，一个HTML字符串输出描述
有语法错误返回1，没有语法错误返回0示例1
输入:
<div><a></a></div>
输出:
0
示例2
输入:
<div><a></div></a>
输出:
1
C++ 解法, 执行用时: 2ms, 内存消耗: 488KB, 提交时间: 2020-08-21
#include <iostream>
#include <string>
#include <stack>
using namespace std;
//判断是否为属性
int isPro(string str, int& i)
{
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z') i++;
while (str[i] == ' ') i++;
if (str[i] == '=')
{
while (str[++i] == ' ');
if (str[i] == '\"')
{
++i;
while (str[i] != '"' && i < str.size()) i++;
if (str[i] == '"') //可能是属性
{
if(str[i] == ' ')
return 0;
else
{
while (str[i+1] != ' ' && str[i+1] != '<' && str[i+1] != '/' && str[i+1] != '>' && str[i+1] != '\0')
{
if (str[++i] == '=')
return 1;
}
return 0;
}
}
}
}
else if(str[i] == '/' || str[i] == '>' || str[i] == '<'
|| str[i] == '\0'|| (str[i] >= 'a' && str[i] <= 'z'))
{
i--;
return 0;
}
}
return 1; //不符合属性格式要求，返回1
}
//判断是否为标签
int isTag(string str, int& i, stack<string>& ss)
{
if (str[i++] == '<')
{
//标签名
string tagName;
//判断是否为字母
if (str[i] >= 'a'&&str[i] <= 'z') //可能是起始标签
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
while (str[i] == ' ') i++; //跳过空格
if (str[i] >= 'a' && str[i] <= 'z') //可能是属性
{
if (isPro(str, i)) //判断标签内是否带有属性
{
return 1;
}
else //有属性，跳过全部属性
{
i++;
while (str[i] == ' ') i++;
while (str[i] >= 'a'&&str[i] <= 'z')
{
if (isPro(str, i))
return 1;
while (str[++i] == ' ');
}
}
if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
else if (str[i] == '/' && str[i+1] == '>') //自闭标签
{
++i;
return 0;
}
}
else if (str[i] == '/') //可能是自闭标签
{
return (str[++i] == '>') ? 0:1;
}
else if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
}
else if (str[i] == '/' && !ss.empty() && ss.top()[0] != '/') //结束标签
{
i++;
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '>' && tagName == ss.top())
{
ss.pop();
return 0;
}
}
}
}
//不是标签
return 1;
}
//判断是否符合
int check(string str)
{
stack<string> ss;
//判断是否为标签
for (int i = 0;i < str.size();++i)
{
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '<')
{
if (isTag(str, i, ss))
return 1;
}
else if ((str[i] >= 'a'&&str[i] <= 'z'))// && !ss.empty())
{
if (isPro(str, i))
return 1;
}
else if (str[i] != '"')
{
return 1;
}
}
return ss.empty() ? 0:1;
}
int main(int argc, char** argv)
{
string str;
getline(cin, str);
cout << check(str) << endl;
return 0;
}
C++14 解法, 执行用时: 2ms, 内存消耗: 504KB, 提交时间: 2019-08-21
#include <iostream>
#include <string>
#include <stack>
using namespace std;
//判断是否为属性
int isPro(string str, int& i)
{
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z') i++;
while (str[i] == ' ') i++;
if (str[i] == '=')
{
while (str[++i] == ' ');
if (str[i] == '\"')
{
++i;
while (str[i] != '"' && i < str.size()) i++;
if (str[i] == '"') //可能是属性
{
if(str[i] == ' ')
return 0;
else
{
while (str[i+1] != ' ' && str[i+1] != '<' && str[i+1] != '/' && str[i+1] != '>' && str[i+1] != '\0')
{
if (str[++i] == '=')
return 1;
}
return 0;
}
}
}
}
else if(str[i] == '/' || str[i] == '>' || str[i] == '<'
|| str[i] == '\0'|| (str[i] >= 'a' && str[i] <= 'z'))
{
i--;
return 0;
}
}
return 1; //不符合属性格式要求，返回1
}
//判断是否为标签
int isTag(string str, int& i, stack<string>& ss)
{
if (str[i++] == '<')
{
//标签名
string tagName;
//判断是否为字母
if (str[i] >= 'a'&&str[i] <= 'z') //可能是起始标签
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
while (str[i] == ' ') i++; //跳过空格
if (str[i] >= 'a' && str[i] <= 'z') //可能是属性
{
if (isPro(str, i)) //判断标签内是否带有属性
{
return 1;
}
else //有属性，跳过全部属性
{
i++;
while (str[i] == ' ') i++;
while (str[i] >= 'a'&&str[i] <= 'z')
{
if (isPro(str, i))
return 1;
while (str[++i] == ' ');
}
}
if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
else if (str[i] == '/' && str[i+1] == '>') //自闭标签
{
++i;
return 0;
}
}
else if (str[i] == '/') //可能是自闭标签
{
return (str[++i] == '>') ? 0:1;
}
else if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
}
else if (str[i] == '/' && !ss.empty() && ss.top()[0] != '/') //结束标签
{
i++;
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '>' && tagName == ss.top())
{
ss.pop();
return 0;
}
}
}
}
//不是标签
return 1;
}
//判断是否符合
int check(string str)
{
stack<string> ss;
//判断是否为标签
for (int i = 0;i < str.size();++i)
{
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '<')
{
if (isTag(str, i, ss))
return 1;
}
else if ((str[i] >= 'a'&&str[i] <= 'z'))// && !ss.empty())
{
if (isPro(str, i))
return 1;
}
else if (str[i] != '"')
{
return 1;
}
}
return ss.empty() ? 0:1;
}
int main(int argc, char** argv)
{
string str;
getline(cin, str);
cout << check(str) << endl;
return 0;
}
C++ 解法, 执行用时: 3ms, 内存消耗: 388KB, 提交时间: 2021-03-25
#include<bits/stdc++.h>
using namespace std;
int main(){
string s;
getline(cin,s);
if(s.back()!='>'){
cout<<1;
return 0;
}
stack<string> st;
string str="";
bool flag=false; //是否需要记录
bool zibihe=false;
bool yinhao=false;
for(int i=0;i<s.length();i++){
// cout<<i<<" ";
if(s[i]=='"' && s[i-1]=='='){
yinhao=true;
}else if(s[i]=='"' && yinhao){
yinhao=false;
}
if(yinhao){
continue;
}
if(s[i]=='<'){
if(str!=""){
if(!st.empty() && st.top()==str){
st.pop();
}else {
//cout<<str<<endl;
st.push(str);
}
}
str="";
flag=true;
}else if(s[i]=='/'){
if(s[i-1]!='<'){
//<div/>自闭和的情况
str="";
flag=false;
zibihe=true;
}
}else if(s[i]=='>'){
//cout<<">"<<str<<endl;
if(!zibihe){
//查看栈中的元素是否为str
if(!st.empty() && st.top()==str){
st.pop();
}else {
//cout<<str<<endl;
st.push(str);
}
str="";
flag=false;
}else{
zibihe=false;
}
}else if(s[i]==' '){
flag=false;
}else{
if(flag){
str.push_back(s[i]);
}
}
}
if(st.empty()){
cout<<0;
}else{
cout<<1;
}
return 0;
}
C++14 解法, 执行用时: 3ms, 内存消耗: 476KB, 提交时间: 2020-05-20
#include <iostream>
#include <string>
#include <stack>
using namespace std;
//判断是否为属性
int isPro(string str, int& i)
{
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z') i++;
while (str[i] == ' ') i++;
if (str[i] == '=')
{
while (str[++i] == ' ');
if (str[i] == '\"')
{
++i;
while (str[i] != '"' && i < str.size()) i++;
if (str[i] == '"') //可能是属性
{
if(str[i] == ' ')
return 0;
else
{
while (str[i+1] != ' ' && str[i+1] != '<' && str[i+1] != '/' && str[i+1] != '>' && str[i+1] != '\0')
{
if (str[++i] == '=')
return 1;
}
return 0;
}
}
}
}
else if(str[i] == '/' || str[i] == '>' || str[i] == '<'
|| str[i] == '\0'|| (str[i] >= 'a' && str[i] <= 'z'))
{
i--;
return 0;
}
}
return 1; //不符合属性格式要求，返回1
}
//判断是否为标签
int isTag(string str, int& i, stack<string>& ss)
{
if (str[i++] == '<')
{
//标签名
string tagName;
//判断是否为字母
if (str[i] >= 'a'&&str[i] <= 'z') //可能是起始标签
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
while (str[i] == ' ') i++; //跳过空格
if (str[i] >= 'a' && str[i] <= 'z') //可能是属性
{
if (isPro(str, i)) //判断标签内是否带有属性
{
return 1;
}
else //有属性，跳过全部属性
{
i++;
while (str[i] == ' ') i++;
while (str[i] >= 'a'&&str[i] <= 'z')
{
if (isPro(str, i))
return 1;
while (str[++i] == ' ');
}
}
if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
else if (str[i] == '/' && str[i+1] == '>') //自闭标签
{
++i;
return 0;
}
}
else if (str[i] == '/') //可能是自闭标签
{
return (str[++i] == '>') ? 0:1;
}
else if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
}
else if (str[i] == '/' && !ss.empty() && ss.top()[0] != '/') //结束标签
{
i++;
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '>' && tagName == ss.top())
{
ss.pop();
return 0;
}
}
}
}
//不是标签
return 1;
}
//判断是否符合
int check(string str)
{
stack<string> ss;
//判断是否为标签
for (int i = 0;i < str.size();++i)
{
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '<')
{
if (isTag(str, i, ss))
return 1;
}
else if ((str[i] >= 'a'&&str[i] <= 'z'))// && !ss.empty())
{
if (isPro(str, i))
return 1;
}
else if (str[i] != '"')
{
return 1;
}
}
return ss.empty() ? 0:1;
}
int main(int argc, char** argv)
{
string str;
getline(cin, str);
cout << check(str) << endl;
return 0;
}
C++ 解法, 执行用时: 3ms, 内存消耗: 480KB, 提交时间: 2019-08-15
#include <iostream>
#include <string>
#include <stack>
using namespace std;
//判断是否为属性
int isPro(string str, int& i)
{
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z') i++;
while (str[i] == ' ') i++;
if (str[i] == '=')
{
while (str[++i] == ' ');
if (str[i] == '\"')
{
++i;
while (str[i] != '"' && i < str.size()) i++;
if (str[i] == '"') //可能是属性
{
if(str[i] == ' ')
return 0;
else
{
while (str[i+1] != ' ' && str[i+1] != '<' && str[i+1] != '/' && str[i+1] != '>' && str[i+1] != '\0')
{
if (str[++i] == '=')
return 1;
}
return 0;
}
}
}
}
else if(str[i] == '/' || str[i] == '>' || str[i] == '<'
|| str[i] == '\0'|| (str[i] >= 'a' && str[i] <= 'z'))
{
i--;
return 0;
}
}
return 1; //不符合属性格式要求，返回1
}
//判断是否为标签
int isTag(string str, int& i, stack<string>& ss)
{
if (str[i++] == '<')
{
//标签名
string tagName;
//判断是否为字母
if (str[i] >= 'a'&&str[i] <= 'z') //可能是起始标签
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
while (str[i] == ' ') i++; //跳过空格
if (str[i] >= 'a' && str[i] <= 'z') //可能是属性
{
if (isPro(str, i)) //判断标签内是否带有属性
{
return 1;
}
else //有属性，跳过全部属性
{
i++;
while (str[i] == ' ') i++;
while (str[i] >= 'a'&&str[i] <= 'z')
{
if (isPro(str, i))
return 1;
while (str[++i] == ' ');
}
}
if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
else if (str[i] == '/' && str[i+1] == '>') //自闭标签
{
++i;
return 0;
}
}
else if (str[i] == '/') //可能是自闭标签
{
return (str[++i] == '>') ? 0:1;
}
else if (str[i] == '>') //起始标签
{
ss.push(tagName);
return 0;
}
}
else if (str[i] == '/' && !ss.empty() && ss.top()[0] != '/') //结束标签
{
i++;
if (str[i] >= 'a'&&str[i] <= 'z')
{
while (str[i] >= 'a'&&str[i] <= 'z')
{
tagName += str[i++];
}
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '>' && tagName == ss.top())
{
ss.pop();
return 0;
}
}
}
}
//不是标签
return 1;
}
//判断是否符合
int check(string str)
{
stack<string> ss;
//判断是否为标签
for (int i = 0;i < str.size();++i)
{
//跳过空格
while (str[i] == ' ') i++;
if (str[i] == '<')
{
if (isTag(str, i, ss))
return 1;
}
else if ((str[i] >= 'a'&&str[i] <= 'z'))// && !ss.empty())
{
if (isPro(str, i))
return 1;
}
else if (str[i] != '"')
{
return 1;
}
}
return ss.empty() ? 0:1;
}
int main(int argc, char** argv)
{
string str;
getline(cin, str);
cout << check(str) << endl;
return 0;
}