Submission #1288755

#	Time	Username	Problem	Language	Result	Execution time	Memory
1288755		TrieTr	The Kingdom of JOIOI (JOI17_joioi)	C++20	100 / 100	1008 ms	16260 KiB

joioi

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

void local() {
    #define taskname ""
    if(fopen(taskname".inp", "r")) {
        freopen(taskname".inp", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
}

#define ll long long
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

template <class X, class Y> bool mini(X& x, Y y) {return x > y ? x = y, true : false;}
template <class X, class Y> bool maxi(X& x, Y y) {return x < y ? x = y, true : false;}

const int N = 2e3 + 5;

int n, m;
vector<vector<int>> a;

int h[N], sf[N];
bool pls_check_2(int x, bool t) {
    int ma = -2e9, mi = 2e9;
    if(t) {
        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= m; j++) {
                a[i][j] = -a[i][j];
            }
        }
    }
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++) {
            maxi(ma, a[i][j]);
            mini(mi, a[i][j]);
        }
    }
    h[n + 1] = m;
    for(int i = n; i > 0; i--) {
        h[i] = 0;
        for(int j = 1; j <= m; j++) {
            if(ma - a[i][j] > x) break;
            h[i] = j;
        }
        if(i == 1) h[i] = min(h[i], m - 1);
        mini(h[i], h[i + 1]);
    }
    ma = -2e9, mi = 2e9;
    for(int i = 1; i <= n; i++) {
        for(int j = h[i] + 1; j <= m; j++) {
            maxi(ma, a[i][j]);
            mini(mi, a[i][j]);
        }
    }
    if(t) {
        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= m; j++) {
                a[i][j] = -a[i][j];
            }
        }
    }
    return ma - mi <= x;
}

bool pls_check(int x, bool t) {
    if(t) {
        for(int i = 1; i * 2 <= n; i++) {
            swap(a[i], a[n - i + 1]);
        }
    }

    bool ok = pls_check_2(x, 0) || pls_check_2(x, 1);

    if(t) {
        for(int i = 1; i * 2 <= n; i++) {
            swap(a[i], a[n - i + 1]);
        }
    }

    return ok;
}

bool check(int x) {
    return pls_check(x, 0) || pls_check(x, 1); 
}

int main() {
    fastio; local();
    cin >> n >> m;
    a.resize(n + 5, vector<int>(m + 5));
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++) {
            cin >> a[i][j];
        }
    }
    int lo = 0, hi = 1e9, res = -1;
    while(lo <= hi) {
        int mid = (lo + hi) >> 1;
        if(check(mid)) hi = (res = mid) - 1;
        else lo = mid + 1;
    }
    cout << res;
}

Compilation message (stderr)

joioi.cpp: In function 'void local()':
joioi.cpp:7:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
joioi.cpp:8:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40