Error in the Array

Question

I am a 10th grade student have just started competitive programming. I was recently was solving this.

While trying to solve this question I encountered this error.

prog.cpp:32:43: error: invalid types ‘[int*]’ for array subscript std::swap(a[p], *std::min_element[b,b+n]); ^ I tried to find a solution but have been stuck on this problem for almost a day.

This is my code:

#include <iostream>
#include <list>
#include <algorithm>
#include <functional>
#include <bits/stdc++.h>

using namespace std;


int main(){
  int n,k,a[100005]={0},b[100005]={0};
  cin>>n>>k;
  for(int i=0;i<n;i++)
  cin>>a[i];
  for(int i=0;i<n;i++)
  cin>>b[i];
  sort(a,a+n);
  sort(b,b+n);
  int one = 0, two = 0, p = n - 1, j = n - 1;

  for ( k>=0;k--) {
    if(k==0){
      cout<<*std::max_element(a,a+n)+*std::min_element(b,b+n)<< "\n";
    }

    if (a[p]>b[j]) {
      std::swap(b[j], *std::min_element[a,a+n]);
      j--;

      one++;
    }
    if (a[p]<b[j]) {
      std::swap(a[p], *std::min_element[b,b+n]);
      p--;
      two++;

    }
  }
  return (0);
}

I would really appreciate if som eone would tell me what I am doing wrong. Also, please point out to anyways I can make my code better.

I will certainly read it Sir. But I would really appreciate if you point to the specific mistake in my code. — Abhijith Chadnran, Jul 10 '18 at 14:46
`min_element` is a function so call it with parenthesis () not square brackets [] — acraig5075, Jul 10 '18 at 14:46
You shouldn't include `, it's an internal implementation detail of the (some) standard library implementations. — Useless, Jul 10 '18 at 14:55

Bruno Hendrickx · Answer 1 · 2018-07-12T06:42:37.380

To improve your coding style, I suggest reading the linux kernel coding style document. Although it's not meant for C++, it can still be applied here.

Concerning the code itself, it feels like your getting ahead of yourself. I've cleaned it up a bit. It compiles with g++.

#include <iostream>
#include <list>
#include <algorithm>
#include <functional>
#include <bits/stdc++.h>

using namespace std;


int main(){
    int n,k,a[100005]={0},b[100005]={0};
    cin>>n>>k;
    for(int i=0;i<n;i++){
        cin>>a[i];
    }
    for(int i=0;i<n;i++){
        cin>>b[i];
    }
    sort(a,a+n);
    sort(b,b+n);
    int one = 0, two = 0, p = n - 1, j = n - 1;

    for (;k>=0;k--) {
        if(k==0){
            cout<<*max_element(a,a+n)+*min_element(b,b+n)<< "\n";
        }
        if (a[p]>b[j]) {
            swap(b[j], *min_element(a,a+n));
            j--;
            one++;
        }
        if (a[p]<b[j]) {
            swap(a[p], *min_element(b,b+n));
            p--;
        }
    }
    return 0;
}

Here's an overview of the things I changed:

Used scoping '{}' to improve readability. It makes it much more clear what code is executed within a loop or if/else statement.
Used tabs and spaces consistently throughout your snippet of code.
Used the statement 'using namespace std;'. This basically means that everything within the standard library can be addressed without 'std::' in front of it. Hence 'std::swap()' becomes 'swap()' and so on. Do note that this is considered bad practice. Read the following on scopes and namespaces to understand them better.
Changed the for loop to 'for(;k>=0;k--)'.A for loop typically has three items separated by semi-colons within the parenthesis. Item 1 is the initialization, you're not using it here. Item 2 is the condition to check, here 'k>=0'. Item 3 is the increment. Read this for more information. You can leave all three items blank (creating an infinite loop), but the two semi-colons need to be there.

Thank You @Bruno Hendrickx, for such an informative answer. Will definitely look forward to all the improvements that you have suggested — Abhijith Chadnran, Jul 10 '18 at 16:06

Error in the Array

1 Answers1