Attribute Parser C++
Problem Statement :
This challenge works with a custom-designed markup language HRML. In HRML, each element consists of a starting and ending tag, and there are attributes associated with each tag. Only starting tags can have attributes. We can call an attribute by referencing the tag, followed by a tilde, '~' and the name of the attribute. The tags may also be nested. The opening tags follow the format: <tag-name attribute1-name = "value1" attribute2-name = "value2" ...> The closing tags follow the format: </tag-name> The attributes are referenced as: tag1~value tag1.tag2~name Given the source code in HRML format consisting of N lines, answer Q queries. For each query, print the value of the attribute specified. Print "Not Found!" if the attribute does not exist. Example HRML listing <tag1 value = "value"> <tag2 name = "name"> <tag3 another="another" final="final"> </tag3> </tag2> </tag1> Queries tag1~value tag1.tag2.tag3~name tag1.tag2~value Here, tag2 is nested within tag1, so attributes of tag2 are accessed as tag1.tag2~<attribute>. Results of the queries are: Query Value tag1~value "value" tag1.tag2.tag3~name "Not Found!" tag1.tag2.tag3~final "final" Input Format The first line consists of two space separated integers, N and Q. N specifies the number of lines in the HRML source program. Q specifies the number of queries. The following N lines consist of either an opening tag with zero or more attributes or a closing tag. There is a space after the tag-name, attribute-name, '=' and value.There is no space after the last value. If there are no attributes there is no space after tag name. Constraints 1 <= N <= 20 1 <= Q <= 20 Each line in the source program contains, at most, 200 characters. Every reference to the attributes in the Q queries contains at most 200 characters. All tag names are unique and the HRML source program is logically correct, i.e. valid nesting. A tag can may have no attributes. Output Format Print the value of the attribute for each query. Print "Not Found!" without quotes if the attribute does not exist.
Solution :
Solution in C :
#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <map>
using namespace std;
vector<string> tag_stack;
map<string, string> attrs;
void insert_attr(string & name, string & val) {
string full;
for(string & str : tag_stack)
full += str + ".";
full.pop_back();
full += "~" + name;
attrs[full] = val;
}
int main() {
int n, q;
cin >> n >> q;
for(int i = 0; i < n; ++i) {
char c; cin >> c;
if(cin.peek() == '/') { // close
string cn; cin >> cn;
tag_stack.pop_back();
}
else { //open'
string name;
cin >> name;
if(name.back() == '>') { //no attrs
name.pop_back();
tag_stack.push_back(name);
}
else {
tag_stack.push_back(name);
for(;;) {
string attr_name, attr_val, eq;
cin >> attr_name >> eq >> attr_val;
if(attr_val.back() == '>') { //last attr
attr_val.pop_back();
attr_val.pop_back();
attr_val = attr_val.substr(1);
insert_attr(attr_name, attr_val);
break;
}
else {
attr_val.pop_back();
attr_val = attr_val.substr(1);
insert_attr(attr_name, attr_val);
}
}
}
}
}
for(int i = 0; i < q; ++i) {
string quer;
cin >> quer;
if(attrs.find(quer) != attrs.end())
cout << attrs[quer] << endl;
else
cout << "Not Found!" << endl;
}
return 0;
}
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