Maintaining a frequently changing list of items or storing input/output in a storage device is a common task in programming languages. The recorded items could be university applicants awaiting approval. The list should provide different operations according to various instructions, such as insertion or deletion.
Write a program based on the following functionality definition, which should provide the following commands: add, insert, and remove.
ADD X: Add X to the bottom of the list. This command must be executable on an empty list.
INSERT X N: Insert X before N.
REMOVE X: Remove X from the list.
X and N contain only uppercase English characters.
Sample Inputs/Outputs
| Sample Input(s) | Sample Output(s) |
|---|---|
| EOF inputs: the input items will not repeat. The command "SHOW" indicates the end of input. | The program must output the list in the correct order, with list items separated by a single space. |
| ADD NEVER ADD COLLAR INSERT CAT COLLAR ADD DOG ADD SCARES INSERT ANYTHING CAT REMOVE CAT INSERT THAT SCARES REMOVE COLLAR INSERT WEAR ANYTHING REMOVE DOG ADD CAT INSERT YOUR CAT SHOW | NEVER WEAR ANYTHING THAT SCARES YOUR CAT |
Thought Process
You can use the push_back function of the vector to handle the ADD action. For INSERT, you can iterate through the original array using a for loop, copy its elements to a new array, and determine whether the current data is the one to be inserted. If it is, you can first push_back the specified data and then push_back the original data at that position. The logic for REMOVE is similar to INSERT. After INSERT and REMOVE, you can use the assign function to copy the new array back to the old array.
Sample Code－ZeroJudge A870: List Maker
#include <iostream>
#include <vector>
using namespace std;
int main() {
string command;
vector<string>v;
while (cin >> command && command != "SHOW")
{
if (command == "ADD")
{
string str;
cin >> str;
v.push_back(str);
}
else if (command == "INSERT")
{
string X, N;
cin >> X >> N;
vector<string>tmp;
for (int i = 0; i<v.size(); i++)
{
if (v[i] == N) tmp.push_back(X);
tmp.push_back(v[i]);
}
v.clear();
v.assign(tmp.begin(), tmp.end());
}
else
{
string str;
cin >> str;
vector<string>tmp;
for(int i = 0; i<v.size(); i++)
{
if (v[i] != str) tmp.push_back(v[i]);
}
v.clear();
v.assign(tmp.begin(), tmp.end());
}
}
for (int i = 0; i<v.size(); i++)
{
cout << v[i] << " ";
}
cout << "\n";
}
//ZeroJudge A870
//Dr. SeanXD