Submission #3220258

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define DUMP(x) cerr << #x << "=" << x << endl
#define DUMP2(x, y) cerr<<"("<<#x<<", "<<#y<<") = ("<<x<<", "<<y<<")"<< endl
#define BINARY(x) static_cast<bitset<16> >(x)

#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define REP(i,m,n) for (int i=m;i<(int)(n);i++)

#define in_range(x, y, w, h) (0<=(int)(x) && (int)(x)<(int)(w) && 0<=(int)(y) && (int)(y)<(int)(h))
#define ALL(a) (a).begin(),(a).end()

typedef long long ll;
const int INF   = 1e9;
const ll  INFLL = 1e18;
typedef pair<int, int> PII;
typedef vector<vector<int>> Graph;
int dx[4]={0, -1, 1, 0}, dy[4]={-1, 0, 0, 1};

int main()
{
    ios::sync_with_stdio(false);

    int N; cin >> N;
    vector<ll> A(N); rep(i, N) cin >> A[i];

    vector<ll> sum(N+1);
    rep(i, N) sum[i+1] = sum[i] + A[i];

    ll ans = INFLL;
    for (int b2=1; b2<N-2; b2++) {
        int b1 = -1;
        {
            int ok = 0, ng = b2 - 1;
            while (abs(ok - ng) > 1) {
                int mid = (ok + ng) / 2;
                ll s1 = sum[mid+1], s2 = sum[b2+1] - sum[mid+1];
                (s1 <= s2 ? ok : ng ) = mid;
            }
            ll s1 = sum[ok+1], s2 = sum[b2+1] - sum[ok+1];
            ll ss1 = sum[ng+1], ss2 = sum[b2+1] - sum[ng+1];

            b1 = (abs(s2-s1) < abs(ss2-ss1) ? ok : ng);
        }

        int b3 = -1;
        {
            int ok = b2+1, ng = N - 1;
            while (abs(ok - ng) > 1) {
                int mid = (ok + ng) / 2;
                ll s1 = sum[mid+1] - sum[b2+1], s2 = sum[N] - sum[mid+1];
                (s1 <= s2 ? ok : ng ) = mid;
            }
            ll s1 = sum[ok+1] - sum[b2+1], s2 = sum[N] - sum[ok+1];
            ll ss1 = sum[ng+1] - sum[b2+1], ss2 = sum[N] - sum[ng+1];

            b3 = (abs(s2-s1) < abs(ss2-ss1) ? ok : ng);
        }

        ll s1 = sum[b1+1] - sum[0];
        ll s2 = sum[b2+1] - sum[b1+1];
        ll s3 = sum[b3+1] - sum[b2+1];
        ll s4 = sum[N] - sum[b3+1];


        // if (ans > max({s1, s2, s3, s4}) - min({s1, s2, s3, s4})) {
        //  cerr << "b1, b2, b3 = " << b1 << " " << b2 << " " << b3 << endl;
        //  cerr << "s1, s2, s3, s4 = " << s1 << " " << s2 << " " << s3 << " " << s4 << endl;
        // }
        ans = min(ans, max({s1, s2, s3, s4}) - min({s1, s2, s3, s4}));
    }

    cout << ans << endl;
}

Submission Info

Judge Result