Algorithm Standard Template Library

#1

What is the use i mean why do we use STL???if we have all the algorithms …why do we use of STL and plus how many are there??? is there any website on which i can find out so i can use STL

#2

Hi @akshat42bajpai
STL is there just to make some things simpler… different stl functions need different header files…
Suppose u have an array and u want to sort it, then using stl u can perform that operation in just one line… u can google can find more about different stl functions available…

#3

hi @akshat42bajpai
is there still anything??

#4

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#5

This is a leetcode question vaibhav …i haven’t studied OOPS or vector yet can you please tell me how should i do this using array

#6


This is my code for the above question can you please help me

#7

hi @akshat42bajpai

vector<int> twoSum(vector<int>& nums, int target) {
        vector<int> v;
        for(int i=0;i<nums.size()-1;i++){
            for(int j=i+1;j<nums.size();j++){
                if(nums[i] + nums[j] == target){
                    v.push_back(i);
                    v.push_back(j);
                    break;
                }
            }
        }
        return v;
        
    }

this is a simple brute force way…

#8

vaibhav one more question is that i have still not covered a lot of DSA…i wanted to know that whenever i open leetcode or gfg to solve questions…the code editor already has syntax written as class public void { and then we have to write the code in those curly braces… i wanted to know that i am still on bitmasking…but still till now i don’t write code with this syntax???/ In which upcoming particular topic i will be covering this stuff?

#9

and the code you send me how do i take the user input if the size is undefined??

#10

hi @akshat42bajpai
so basically what happens on leetcode and geeksforgeeks is that u are just provided with the function part… u don’t have to write the code from scratch…

#11 
#include <iostream>
using namespace std;
int main() {
    int n;
    cin>>n;
    vector<int> v;
    for(int i=0;i<n;i++){
        int no;
        cin>>no;
        v.push_back(no);
    }
}
#12

okay but what about that text of class public void…in which topic i will be covering that?? and if i want to earse that and write the code in my way can i do that??

#13

hi @akshat42bajpai
actually what u are taking about is not taught anywhere… as i said its just function, which u have to complete… rest i dint think u can erase there and write code from scratch… if u want to write code from scratch then go for sites like codechef, codeforces…

#14

#include<bits/stdc++.h>

using namespace std;

vector TwoSum(vector&nums, int target){

vector v;

for(int i=0;i<nums.size();i++){
 for(int j=i+1;j<nums.size();j++){
     if(nums[i] + nums[j]==target){
         v.push_back(i);
         v.push_back(j);
         break;
     }
 }

}
return v;

}
int main(){
int n;
cin>>n;
vector nums;
for(int i=0;i<n;i++){
int no;
cin>>no;
nums.push_back(no);
}
int target;
cin>>target;
result = TwoSum(nums, target);
cout<<result;
}

it’s still not working vaibhav can you please help??

#15


this is the code if you can help it’s the same leetcode question

#16

hi @akshat42bajpai
U are returning vector from function… so in main write as

 vector<int> result

and for printing and traverse over result vector…

#17


I did it what you said and in coding blocks IDE the output is coming as well but in leetcode IDE it is showing this error

Line 51: Char 25: error: use of undeclared identifier ‘Solution’
vector ret = Solution().twoSum(param_1, param_2); return ret;
^

#18

hi @akshat42bajpai
its working fine…

#include<bits/stdc++.h>

using namespace std;

vector<int> TwoSum(vector<int>&nums, int target){

    vector<int> v;
    
    for(int i=0;i<nums.size();i++){
        for(int j=i+1;j<nums.size();j++){
            if(nums[i] + nums[j]==target){
                v.push_back(i);
                v.push_back(j);
                break;
            }
        }
    }
    return v;
}
int main(){
    int n;
    cin>>n;
    vector<int> nums;
    for(int i=0;i<n;i++){
        int no;
        cin>>no;
        nums.push_back(no);
    }
    int target;
    cin>>target;
    vector<int> result = TwoSum(nums, target);
    for(int x:result){
        cout<<x<<" ";
    }
    
}