SEDARR - Editorial

PROBLEM LINK:

Practice
Contest: Division 1
Contest: Division 2

Setter: Bhavyesh Desai
Tester: Rahul Dugar
Editorialist: Taranpreet Singh

DIFFICULTY

Cakewalk

PREREQUISITES

None

PROBLEM

Given a sequence of N positive integers and an integer K, determine the minimum number of operations to be applied so that sum of elements is divisible by K.

An operation is defined here as choosing any element of a given sequence and replacing it with any positive integer.

QUICK EXPLANATION

Either the sum of elements is already divisible by K, or we need to change one element so that sum of elements becomes multiple of K. So the answer is always either 0 or 1, depending upon the sum of the given array.

EXPLANATION

Firstly, let’s consider the case when the sum of the given elements is already a multiple of K. Hence, no operations are required.

In all other cases, let us prove that by changing one element, we can always make the sum of elements a multiple of K. Let’s assume the sum of elements is S and S \bmod K = R, we can replace any integer x by x-R, So the sum of the resulting array becomes multiple of S.

But what if x-R is not a positive integer, since operation asks to replace with a positive integer?
Easy, instead of replacing by x-R, replace the element by x+K-R and since K > R, x+K-R > x, hence a positive integer.

TIME COMPLEXITY

The time complexity is O(N) per test case.
Memory complexity O(1).

SOLUTIONS

Setter's Solution
Tester's Solution
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#ifndef rd
#define trace(...)
#define endl '\n'
#endif
#define pb push_back
#define fi first
#define se second
#define int long long
typedef long long ll;
typedef long double f80;
#define double long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define sz(x) ((long long)x.size())
#define fr(a,b,c) for(int a=b; a<=c; a++)
#define rep(a,b,c) for(int a=b; a<c; a++)
#define trav(a,x) for(auto &a:x)
#define all(con) con.begin(),con.end()
const ll infl=0x3f3f3f3f3f3f3f3fLL;
const int infi=0x3f3f3f3f;
const int mod=998244353;
//const int mod=1000000007;
typedef vector<int> vi;
typedef vector<ll> vl;

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> oset;
auto clk=clock();
mt19937_64 rang(chrono::high_resolution_clock::now().time_since_epoch().count());
int rng(int lim) {
	uniform_int_distribution<int> uid(0,lim-1);
	return uid(rang);
}

int powm(int a, int b) {
	int res=1;
	while(b) {
		if(b&1)
			res=(res*a)%mod;
		a=(a*a)%mod;
		b>>=1;
	}
	return res;
}

long long readInt(long long l, long long r, char endd) {
	long long x=0;
	int cnt=0;
	int fi=-1;
	bool is_neg=false;
	while(true) {
		char g=getchar();
		if(g=='-') {
			assert(fi==-1);
			is_neg=true;
			continue;
		}
		if('0'<=g&&g<='9') {
			x*=10;
			x+=g-'0';
			if(cnt==0) {
				fi=g-'0';
			}
			cnt++;
			assert(fi!=0 || cnt==1);
			assert(fi!=0 || is_neg==false);

			assert(!(cnt>19 || ( cnt==19 && fi>1) ));
		} else if(g==endd) {
			if(is_neg) {
				x=-x;
			}
			assert(l<=x&&x<=r);
			return x;
		} else {
			assert(false);
		}
	}
}
string readString(int l, int r, char endd) {
	string ret="";
	int cnt=0;
	while(true) {
		char g=getchar();
		assert(g!=-1);
		if(g==endd) {
			break;
		}
		cnt++;
		ret+=g;
	}
	assert(l<=cnt&&cnt<=r);
	return ret;
}
long long readIntSp(long long l, long long r) {
	return readInt(l,r,' ');
}
long long readIntLn(long long l, long long r) {
	return readInt(l,r,'\n');
}
string readStringLn(int l, int r) {
	return readString(l,r,'\n');
}
string readStringSp(int l, int r) {
	return readString(l,r,' ');
}

void solve() {
	int n=readIntSp(1,100),k=readIntLn(1,100000);
	vi a(n);
	rep(i,0,n)
		if(i!=n-1)
			a[i]=readIntSp(1,100000);
		else
			a[i]=readIntLn(1,100000);
	int su=accumulate(all(a), 0LL);
	if(su%k)
		cout<<1<<endl;
	else
		cout<<0<<endl;
}

signed main() {
	ios_base::sync_with_stdio(0),cin.tie(0);
	srand(chrono::high_resolution_clock::now().time_since_epoch().count());
	cout<<fixed<<setprecision(7);
	int t=readIntLn(1,1000);
//	int t;
//	cin>>t;
	fr(i,1,t)
		solve();
	assert(getchar()==EOF);
#ifdef rd
	cerr<<endl<<endl<<endl<<"Time Elapsed: "<<((double)(clock()-clk))/CLOCKS_PER_SEC<<endl;
#endif
}
Editorialist's Solution
import java.util.*;
import java.io.*;
class SEDARR{
	//SOLUTION BEGIN
	void pre() throws Exception{}
	void solve(int TC) throws Exception{
	    int N = ni(), K = ni();
	    int sum = 0;
	    for(int i = 0; i< N; i++)sum += ni();
	    pn(sum%K == 0?0:1);
	}
	//SOLUTION END
	void hold(boolean b)throws Exception{if(!b)throw new Exception("Hold right there, Sparky!");}
	static boolean multipleTC = true;
	FastReader in;PrintWriter out;
	void run() throws Exception{
	    in = new FastReader();
	    out = new PrintWriter(System.out);
	    //Solution Credits: Taranpreet Singh
	    int T = (multipleTC)?ni():1;
	    pre();for(int t = 1; t<= T; t++)solve(t);
	    out.flush();
	    out.close();
	}
	public static void main(String[] args) throws Exception{
	    new SEDARR().run();
	}
	int bit(long n){return (n==0)?0:(1+bit(n&(n-1)));}
	void p(Object o){out.print(o);}
	void pn(Object o){out.println(o);}
	void pni(Object o){out.println(o);out.flush();}
	String n()throws Exception{return in.next();}
	String nln()throws Exception{return in.nextLine();}
	int ni()throws Exception{return Integer.parseInt(in.next());}
	long nl()throws Exception{return Long.parseLong(in.next());}
	double nd()throws Exception{return Double.parseDouble(in.next());}

	class FastReader{
	    BufferedReader br;
	    StringTokenizer st;
	    public FastReader(){
	        br = new BufferedReader(new InputStreamReader(System.in));
	    }

	    public FastReader(String s) throws Exception{
	        br = new BufferedReader(new FileReader(s));
	    }

	    String next() throws Exception{
	        while (st == null || !st.hasMoreElements()){
	            try{
	                st = new StringTokenizer(br.readLine());
	            }catch (IOException  e){
	                throw new Exception(e.toString());
	            }
	        }
	        return st.nextToken();
	    }

	    String nextLine() throws Exception{
	        String str = "";
	        try{   
	            str = br.readLine();
	        }catch (IOException e){
	            throw new Exception(e.toString());
	        }  
	        return str;
	    }
	}
}

VIDEO EDITORIAL:

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3 Likes

why the solution is not being accepted if i take the sequence as a input in an array

check your code again I am also giving the input as array, i got ac