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Display Table of Food Orders in a Restaurant in C++
Suppose we have an array orders, which represents the orders that customers have done in a restaurant. So, orders[i]=[cust_namei, table_numi, food_itemi] where cust_namei is the customer name, table_numi is the customers table number, and food_itemi is the item customer orders.
We have to return the restaurant's “display table”. Here the “display table” is a table whose row entries denote how many of each food item each table ordered. The first column will be the table number and the remaining columns correspond to each food item in alphabetical order. First row should be a header whose first column is “Table”, followed by the names of the foods.
So, if the input is like orders = [["Amal","3","Paratha"],["Bimal","10","Biryni"],["Amal","3","Fried Chicken"],["Raktim","5","Water"],["Raktim","5","Paratha"],["Deepak","3","Paratha"]], then the output will be [["Table","Biryni","Fried Chicken","Paratha","Water"],["3","0","1","2","0"],["5","0","0","1","1"],["10","1","0","0","0"]]
To solve this, we will follow these steps −
Define one map m
Define one set names
Define one set t
for each element it in order list
insert it[1] into t
ok := true
if ok is false, then −
v = an array after splitting it[2] using blank space
for each element x in v, do
(increase m[it[1], x] by 1)
insert x into names
Otherwise
(increase m[it[1], it[2]] by 1)
insert it[2] into names
Define one 2D array ret
Define an array temp and copy element from names
insert "Table" as the first element into temp
insert temp at the end of ret
for each element it in t, do
Define an array te
insert it at the end of te
for each element x in names, do
insert m[it, x] as string at the end of te
insert te at the end of ret
sort the array ret
return ret
Example
Let us see the following implementation to get better understanding −
#include <bits/stdc++.h>
using namespace std;
void print_vector(vector<vector<string> > v){
cout << "[";
for(int i = 0; i<v.size(); i++){
cout << "[";
for(int j = 0; j <v[i].size(); j++){
cout << v[i][j] << ", ";
}
cout << "],";
}
cout << "]"<<endl;
}
typedef long long int lli;
class Solution {
public:
vector <string> split(string& s, char delimiter){
vector <string> tokens;
string token;
istringstream tokenStream(s);
while(getline(tokenStream, token, delimiter)){
tokens.push_back(token);
}
return tokens;
}
static bool cmp(vector <string>& a, vector <string>& b){
lli an = stol(a[0]);
lli bn = stol(b[0]);
return an < bn;
}
vector<vector<string>> displayTable(vector<vector<string>>& o) {
map <string, map < string, int> >m;
set <string> names;
set <string> t;
for(auto &it : o){
t.insert(it[1]);
bool ok = true;
if(!ok){
vector <string> v = split(it[2], ' ');
for(auto& x : v){
m[it[1]][x]++;
names.insert(x);
}
}
else{
m[it[1]][it[2]]++;
names.insert(it[2]);
}
}
vector < vector <string> > ret;
vector <string> temp(names.begin(), names.end());
temp.insert(temp.begin(), "Table");
ret.push_back(temp);
for(auto& it : t){
vector <string> te;
te.push_back(it);
for(auto& x : names){
te.push_back(to_string(m[it][x]));
}
ret.push_back(te);
}
sort(ret.begin() + 1, ret.end(), cmp);
return ret;
}
};
main(){
Solution ob;
vector<vector<string>> v = {{"Amal","3","Paratha"},{"Bimal","10","Biryni"},{"Amal","3","Fried
Chicken"},{"Raktim","5","Water"},{"Raktim","5","Paratha"},{"Deepak"," 3","Paratha"}};
print_vector(ob.displayTable(v));
}Input
{{"Amal","3","Paratha"},{"Bimal","10","Biryni"},{"Amal","3","Fried Chicken"},{"Raktim","5","Water"},{"Raktim","5","Paratha"},{"Deepak"," 3","Paratha"}}Output
[[Table, Biryni, Fried Chicken, Paratha, Water, ],[3, 0, 1, 2, 0, ],[5, 0, 0, 1, 1, ],[10, 1, 0, 0, 0, ],]
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