PEPPERON - Editorial

grg124 · August 19, 2019, 4:53pm

hey plz help i dont get where my code lags!!

#include<bits/stdc++.h>

using namespace std;

int main(){
//freopen(“input.txt”,“r”,stdin);
//freopen(“output.txt”,“w”,stdout);

ios::sync_with_stdio(0);
cin.tie(0);
int t;
scanf("%d",&t);
while(t--){
    int n;
    scanf("%d",&n);
    char matrix[n][n];
    // input matrix and calculate total sum
    int tsum=0,lsum=0;
    int minn=1000000000;
    for(int i=0;i<n;i++){
        int lrowsum=0,rrowsum=0;
        for(int j=0;j<n;j++){
            scanf("%c",&matrix[i][j]);
            int r=(int)matrix[i][j];
            tsum=tsum+r;
            

            if(j<n/2){
                lsum=lsum+r;
                lrowsum=lrowsum+r;
            }
            else{
                rrowsum=rrowsum+r;
            }
            
                minn=min(abs(2*lsum-tsum-2*abs(lrowsum+rrowsum)),minn);
            
        }
    }

    
    printf("%d\n",minn );

}

return 0;

}

it is giving wrong output !! but my logic maches as given in editorial! plz help i am trying from long time.

aryan12 · August 19, 2019, 5:57pm

In all the loops change prefix operators to postfix operators.

If you don’t know what they are read this.

aryan12 · August 19, 2019, 6:04pm

It is true that your logic is the same as given in the editorial but you are messing up with ascii values.

The ascii value of 0 is 48 and 1 is 49
Thus, r will either be 48 or 49 and not 0 or 1.

That’s your bug which I caught on first glance through he code.

I dont think there should be more

grg124 · August 19, 2019, 7:05pm

but i typecast my value to int

aryan12 · August 19, 2019, 7:33pm

That is the reason…
The character ‘0’ has an decimal value of 48 in the integer list.

If you want more explanation, see ASCII - Simple English Wikipedia, the free encyclopedia

Here, the character ‘0’ has decimal value 48 and character ‘1’ has decimal value 49

thunderboltz · August 20, 2019, 11:17am

Problem:

@erfaniaa

int sum = 0;
		for(int i=0;i<n;i++)
			sum+=a[i];
		int ans = abs(sum);
		for(int i=0;i<n;i++)
		{
			ans = min(ans , abs(sum - 2*a[i]));
		}

Anybody explain me above part of Setter1 Solution.
for 1st Testcase: a[]=1,1,1,1,0,0
for 2nd Testcase: a[]=-2,2,1,-1

what happened after that?
Please, explain logic behind that

ketan_mehta · August 20, 2019, 8:37pm

import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner k = new Scanner(System.in);
int n=k.nextInt();
while(n>0){
int totalstr=k.nextInt();
int arr[][]=new int[totalstr][totalstr];
int leftsum=0,rightsum=0;
k.nextLine();
for(int j=0;j<totalstr;j++){
String str=k.nextLine();

            for(int i=0;i<str.length();i++){
                if(i<str.length()/2){
                    if(str.charAt(i)=='1'){
                        leftsum++;
                        arr[j][i]=1;
                    }
                }else{
                    if(str.charAt(i)=='1'){
                        rightsum++;
                        arr[j][i]=1;
                    }
                }
            }
        }
        if(Math.abs(leftsum-rightsum)==0){
            System.out.println(0);
            return;
        }
        int min=1000;
       for(int a=0;a<arr.length;a++){
           int x=0,y=0;
            for(int b=0;b<arr.length;b++){
              if(arr[a][b]==1&&b<arr.length/2){
                  x++;
              }else if(arr[a][b]==1&&b>=arr.length/2){
                  y++;
                 
              }
            }
         int ans=Math.abs(leftsum-x+y-(rightsum-y+x));
         
          if(min>ans){
              min=ans;
          }
       }  
         System.out.print(min);
 n--;}
    
}}

ketan_mehta · August 20, 2019, 8:37pm

what s the error is in my code

ishaan_007 · August 21, 2019, 5:50am

Here is the python code

syntaxhacker · August 21, 2019, 1:35pm

whats happening here ? what does this sum - 2*a[i])); do ?

jainaayush · August 21, 2019, 2:46pm

why in the solution
ans = min(ans , abs(sum - 2a[i])) is used why can’t we use
ans = sum(a) - 2max(a)
@samarthtandon @ssrivastava990

ssrivastava990 · August 21, 2019, 4:10pm

Because we need to check to each row, instead of just subtract the max…, @syntaxhacker @l_returns @ashokshaun
Pls help regarding this doubt , bcz why we have to check for each value, just subtract Max value, correct me if I m wrong.

sukant007 · August 22, 2019, 1:37am

please help me with my code i am not able to found error in my code , it is passing sample test case but giving wrong answer on submission
here is my code:

#include<bits/stdc++.h>

using namespace std;

int main()
{
int t;
cin>>t;
while(t–)
{
int n;
int ans;
cin>>n;
char pizza[n+1][n+1];
int countf[n+1];
int countl[n+1];
int maxdif=0;
int mindif;
long long int sumf=0,suml=0;
for(int i=1;i<=n;i++)
{

        for(int j=1;j<=n;j++)
        {
            cin>>pizza[i][j];
        }

    }
     for(int i=1;i<=n;i++)
    {
        countf[i]=0;
        for(int j=1;j<=n/2;j++)
        {
            if(pizza[i][j]=='1')
            {
                countf[i]++;
            }
        }
        sumf+=countf[i];
    }
    for(int i=1;i<=n;i++)
    {
        countl[i]=0;
        for(int j=(n/2)+1;j<=n;j++)
        {
            if(pizza[i][j]=='1')
            {
                countl[i]++;

            }

        }
        suml+=countl[i];
        if(abs(countl[i]-countf[i])>maxdif)
            {maxdif=abs(countl[i]-countf[i]);}
    }
    //cout<<sumf<<" "<<suml<<" ";

    mindif=abs(sumf-suml);
    if(mindif==0)
    {
        ans=mindif;
    }

  else
  {
      ans= mindif- (2*maxdif);
  }
if(ans>0)

{
    cout<<ans<<endl;
}
else
{
    cout<<mindif<<endl;
}

}


return 0;

}

ndhola2580 · August 23, 2019, 5:50am

Hi guys,
can anyone tell what’s wrong in this code?
I’m getting wrong answer
Thank you

	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner input = new Scanner(System.in);
		int test,rows,count,overallDiff,min;
		String pizzaGrid[] = new String[10000];
		int diffKeeper[] = new int[10000];
		test = input.nextInt();
		while(test-- > 0) {
		    overallDiff = 0;
		    rows = input.nextInt();
		    for (int i = 0; i < rows; i++) {
		        count = 0;
		        pizzaGrid[i] = input.next();
		        for (int j = 0; j < rows; j++) {
		            if (j < rows/2 && pizzaGrid[i].charAt(j) == '1') {
		                count++;
		            } else if (pizzaGrid[i].charAt(j) == '1') {
		                count--;
		            }
		        }
		        diffKeeper[i] = count*2;
		        overallDiff += count;
		    }
		    //System.out.println(overallDiff);
		    if (overallDiff != 0) {
		        min = overallDiff;
                for (int i = 0; i < rows; i++) {
                    if (Math.abs(overallDiff - diffKeeper[i]) < Math.abs(min)) {
                        min = Math.abs(overallDiff - diffKeeper[i]);
                    }
                }
                System.out.println(min);
		    } else {
		        System.out.println(0);
		    }
		}
	}

lm10_piyush · August 24, 2019, 10:32am

#include<bits/stdc++.h>
#define ll long long
#define mod 1000000007
#define mp make_pair
#define endl “\n”
#define tab " "
#define pb push_back
#define F first
#define S second
#define watch(x) cout<<(#x)<<" = “<<x<<” "
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)

using namespace std;

int main()
{
int t,n,t1,t2,data,ans,L,R;
cin>>t;
while(t–)
{
cin>>n;
int A[n][2];
ans=0;

string s1[n];
for(int i=0;i<n;i++) cin>>s1[i];
  L=R=0; //L,R contains total no. of 1's in left and right respectively

for(int i=0;i<n;i++){
  t1=0;t2=0;
  
for(int j=0;j<n;j++){
  data=(s1[i][j]=='0')?0:1;
  if(j>=0 && j<n/2)
    t1+=data;
  else
    t2+=data;
}
A[i][0]=t1;
A[i][1]=t2;
L+=t1;
R+=t2;

}
// watch(L);
// watch®;

int temp1,temp2;
temp1=L-R;   
ans=abs(temp1);

for(int i=0;i<n;i++)
{
  temp2=abs(temp1-2*(A[i][0]-A[i][1]));
  if(ans>temp2) pur=temp2;
  
}

cout<<ans<<endl;
}

}

sauravrajleaf · September 2, 2019, 1:48pm

why do i get SIGSEGV in my code ?

#include <iostream>
#include<algorithm>
#include<numeric>
#include<vector>
#include<map>
#include<string>
#include<string.h>
#include<math.h>
#define REP(i, a, b)  for (int i = int(a); i <= int(b); i++)
#define NREP(i, a, b) for (int i = int(a); i >= int(b); i--)
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(NULL)
#define circ_inc(i, n) (i + 1) % int(n)
#define circ_dec(i, n) (i + int(n) - 1) % int(n)
#define round(x) (int)((double)int(x) + 0.5)
#define println(x) cout << x << '\n'
#define F first
#define S second
#define INF 1000000000
#define gcd __gcd
#define nset __builtin_popcount
#define pb push_back
#define btoe(x) x.begin(), x.end()
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<long> vl;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vector<int> > vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<string> vs;
typedef map<string, int> msi;
typedef istringstream iss;
int main()
{
	FASTIO;
	int t;
	cin >> t;//testcases
	while (t--) {
		int n;
		cin >> n;
		string s[1000];
		REP(i, 0, n - 1) {
			cin >> s[i];

		}
		int leftsum = 0, rightsum = 0;
		int x = 0, y = 0;
		vi v1;//storing total number of 1s on left for every row
		vi v2;//storing total number of 1s on right for every row
		REP(i, 0, n - 1) {
			x = 0;

			REP(j, 0, n / 2 - 1) {
				if (s[i][j] == '1') {
					leftsum++;
					x++;
				}

			}
			v1.pb(x);

		}
		REP(i, 0, n - 1) {
			y = 0;

			REP(j, n / 2, n - 1) {
				if (s[i][j] == '1') {
					rightsum++;
					y++;
				}

			}
			v2.pb(y);

		}

		if (leftsum - rightsum != 0) {

			vi results;
			REP(i, 0, n - 1) {
				cout << (leftsum - rightsum) - 2 * (v1[i] + v2[i]) << endl;
				if ((leftsum - rightsum) - 2 * (v1[i] + v2[i]) == 0)
					continue;
				results.pb((leftsum - rightsum) - 2 * (v1[i] + v2[i]));
			}
			sort(results.begin(), results.end());
			cout << results[0] << endl;
		}
		else
			cout << "0" << endl;
	}

	return 0;
}

honeyyadav · September 14, 2019, 1:26pm

I know all about prefix and postfix operators. Changing prefix operators to postfix operators doesn’t effect my answer.

krn05 · January 29, 2020, 6:33pm

could anybody tell what’s wrong with my ans, please?

https://www.codechef.com/viewsolution/29249720