89 lines
2.4 KiB
C++
89 lines
2.4 KiB
C++
#include <stdio.h>
|
|
#include <iostream>
|
|
#include <sstream>
|
|
#include <vector>
|
|
using namespace std;
|
|
vector<string> st;
|
|
int tag_type(const string& s) {
|
|
int cnt=0;
|
|
for(int i=0; i<s.size(); ++i) {
|
|
if(s[i]=='/') { cnt++; continue; }
|
|
if(!((s[i]<='z' && s[i]>='a') || (s[i]>='0' && s[i]<='9'))) return 0;
|
|
}
|
|
if(s.size()-cnt==0) return 0;
|
|
if(s[0]=='/' && cnt == 1) return 2;
|
|
if(s[s.size()-1]=='/' && cnt == 1) return 3;
|
|
if(cnt == 0) return 1;
|
|
return 0;
|
|
}
|
|
bool hex(const string& s) {
|
|
if(s.size() <= 1 || s.size()%2==0) return false;
|
|
if(s[0] != 'x') return false;
|
|
for(int i=1; i<s.size(); ++i)
|
|
if( !((s[i]<='F' && s[i] >='A') || (s[i]<='9' && s[i]>='0') || (s[i]<='f' && s[i]>='a')) ) return false;
|
|
return true;
|
|
}
|
|
bool bad_qoute(const string& s) {
|
|
return !(s=="lt" || s=="gt" || s=="amp" || hex(s));
|
|
}
|
|
bool bad_txt(const string& s) {
|
|
string qoute;
|
|
for(int i=0; i<s.size(); ++i)
|
|
if(s[i]=='&') {
|
|
for(int j=i+1; j<s.size() && s[j] != ';'; ++j) qoute += s[j];
|
|
if(bad_qoute(qoute)) return true;
|
|
qoute="";
|
|
}
|
|
else if(s[i]=='<' || s[i] =='>') return true;
|
|
else if(s[i]>127 || s[i]<32) return true;
|
|
return false;
|
|
}
|
|
void get_l(stringstream& os, string& s, char del) {
|
|
char t;
|
|
while(!os.eof()) {
|
|
os >> t;
|
|
if(t==del) return;
|
|
s += t;
|
|
}
|
|
}
|
|
int main() {
|
|
string ln;
|
|
while(getline(cin, ln)) {
|
|
stringstream ss(ln);
|
|
st.clear();
|
|
string s;
|
|
int inv=0;
|
|
while(!ss.eof()) {
|
|
s="";
|
|
getline(ss,s,'<');
|
|
if(bad_txt(s)) {
|
|
inv=1;
|
|
break;
|
|
}
|
|
if(ss.eof()) break;
|
|
s="";
|
|
getline(ss,s,'>');
|
|
if(ss.eof()) {
|
|
inv=4;
|
|
break;
|
|
}
|
|
int tty = tag_type(s);
|
|
if(tty==0) {
|
|
inv=2;
|
|
break;
|
|
}
|
|
else if(tty==1) st.push_back(s);
|
|
else if(tty==2) {
|
|
if(st.size()==0 || st.back() != s.substr(1)) {
|
|
inv=3;
|
|
break;
|
|
}
|
|
else st.pop_back();
|
|
}
|
|
}
|
|
if(inv || st.size() > 0) puts("invalid");
|
|
else puts("valid");
|
|
}
|
|
return 0;
|
|
}
|