HackerEarth Bela Jornada problem solution

HackerRank Bela Jornada problem solution

HackerEarth Bela Jornada problem solution.

#pragma GCC optimize("O3")
#include <bits/stdc++.h>

#define ll long long
#define ull unsigned long long
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define be begin()
#define en end()
#define all(x) (x).begin(),(x).end()
#define alli(a, n, k) (a+k),(a+n+k)
#define REP(i, a, b, k) for(__typeof(a) i = a;i < b;i += k)
#define REPI(i, a, b, k) for(__typeof(a) i = a;i > b;i -= k)
#define REPITER(it, a) for(__typeof(a.begin()) it = a.begin();it != a.end(); ++it)

#define y0 sdkfaslhagaklsldk
#define y1 aasdfasdfasdf
#define yn askfhwqriuperikldjk
#define j1 assdgsdgasghsf
#define tm sdfjahlfasfh
#define lr asgasgash
#define norm asdfasdgasdgsd
#define have adsgagshdshfhds

#define eps 1e-6
#define pi 3.141592653589793

using namespace std;

template<class T> inline T gcd(T a, T b) { while(b) b ^= a ^= b ^= a %= b; return a; }
template<class T> inline T mod(T x) { if(x < 0) return -x; else return x; }

typedef vector<int> VII;
typedef vector<ll> VLL;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
typedef pair<int, PII > PPII;
typedef vector< PII > VPII;
typedef vector< PPII > VPPI;

const ll MOD = 1e10;
const int INF = 1e9;
// Template End

const int MAX = 1e5 + 5;
int a[MAX];

int main(int argc, char* argv[])
{
    if(argc == 2 or argc == 3) freopen(argv[1], "r", stdin);
    if(argc == 3) freopen(argv[2], "w", stdout);
    int n;
    long long ans = 0, sum = 0, sum1 = 0;
    cin >> n;
    REP(i, 0, n, 1)
    {
        cin >> a[i];
        sum += a[i];
    }
    REP(i, 0, n, 1)
    {
        sum1 += a[i];
        ans = max(ans, (sum1 * (sum - sum1)));
    }
    cout << ans << endl;
    return 0;
}

Second solution

#include <iostream>
#include <stdio.h>
#include <assert.h>
#include <algorithm>
using namespace std;

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 || g==-1){
            if(is_neg){
                x= -x;
            }
            assert(l<=x && x<=r);
            return x;
        } else {
            assert(false);
        }
    }
}
string readString(char endd){
    string ret="";
    while(true){
        char g=getchar();
        assert(g!=-1);
        if(g==endd){
            break;
        }
        
        ret+=g;
    }
    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(){
    return readString('\n');
}
string readStringSp(){
    return readString(' ');
}

int n;
long long arr[100100];
long long sol=0;
long long sm=0,sm1=0;
int main(){
    n=readIntLn(2,100000);
    for(int i=1;i<=n;i++){
        if(i==n){
            arr[i]=readInt(1,10000,-1);
        } else {
            arr[i]=readIntSp(1,10000);
        }
        sm+=arr[i];
    }
    for(int i=1;i<n;i++){
        sm1+=arr[i];
        sol=max(sol,sm1*(sm-sm1));
    }
    cout<<sol<<endl;
    assert(getchar()==-1);
}