Submission #1109937

#	Time	Username	Problem	Language	Result	Execution time	Memory
1109937		ljtunas	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	1250 ms	70724 KiB

joioi

// author : anhtun_hi , nqg
#include <bits/stdc++.h>
#define ll long long
#define ii pair<ll, ll>
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define reset(h, v)    memset(h, v, sizeof h)
#define Forv(i, a)     for(auto& i : a)
#define For(i, a, b)   for(int i = a; i <= b; ++i)
#define Ford(i, a, b)  for(int i = a; i >= b; --i)
#define c_bit(i)     __builtin_popcountll(i)
#define Bit(mask, i)    ((mask >> i) & 1LL)
#define onbit(mask, i)  ((mask) bitor (1LL << i))
#define offbit(mask, i) ((mask) &~ (1LL << i))
using namespace std;
namespace std {
    template <typename T, int D>
    struct _vector : public vector <_vector <T, D - 1>> {
        static_assert(D >= 1, "Dimension must be positive!");
        template <typename... Args>
        _vector(int n = 0, Args... args) : vector <_vector <T, D - 1>> (n, _vector <T, D - 1> (args...)) {}
    };
    template <typename T> struct _vector <T, 1> : public vector <T> {
        _vector(int n = 0, const T& val = T()) : vector <T> (n, val) {}
    };
    template <class A, class B> bool minimize(A &a, B b){return a > b ? a = b, true : false;}
    template <class A, class B> bool maximize(A &a, B b){return a < b ? a = b, true : false;}
}
const int dx[] = {0, 0, +1, -1}, dy[] = {-1, +1, 0, 0}, LOG = 20, base = 311, inf = 1e9 + 5;
const int MAXN = 2e3 + 5;
const  ll  mod = 1e9 + 7;
const  ll   oo = 1e18;

//#define int long long

int n, m, mx, mn = inf; vector<vector<int>> a, b;
bool vs[MAXN][MAXN];
bool check(int val){
    For(i, 0, n - 1){
        For(j, 0, m - 1){
            b[i][j] = 0;
            if(a[i][j] <= mn + val) b[i][j] |= 1;
            if(a[i][j] >= mx - val) b[i][j] |= 2;
            if(b[i][j] == 0) return false;
        }
    }
//    cerr << '*';
    For(t, 1, 2){
        bool ok = true;
        int len = m - 1;
        For(i, 0, n - 1){
            int st = m, ed = -1;
            For(j, 0, m - 1) if(b[i][j] == t) ed = j;
            Ford(j, m - 1, 0) if(b[i][j] == (t ^ 3)) st = j;
            minimize(len, st - 1);
            if(len < ed) ok = false;
        }
        if(ok) return true;
        ok = true;
        len = m - 1;
        Ford(i, n - 1, 0){
            int st = m, ed = -1;
            For(j, 0, m - 1) if(b[i][j] == t) ed = j;
            Ford(j, m - 1, 0) if(b[i][j] == (t ^ 3)) st = j;
            minimize(len, st - 1);
            if(len < ed) ok = false;
        }
        if(ok) return true;
    }
    return false;
}

void Solve() {
    cin >> n >> m;
    a.assign(n, vector<int>(m, 0)), b.assign(n, vector<int>(m, 0));
    For(i, 0, n - 1) For(j, 0, m - 1) cin >> a[i][j], minimize(mn, a[i][j]), maximize(mx, a[i][j]);
     int l = -1, r = inf;
    while(r - l > 1){
        int mid = l + r >> 1;
        if(check(mid)) r = mid;
        else l = mid;
    }
    cout << r << '\n';
}

int32_t main() {
    cin.tie(0) -> sync_with_stdio(0);
    if(fopen("JOI17_joioi.inp", "r")) {
        freopen("JOI17_joioi.inp", "r", stdin);
        freopen("JOI17_joioi.out", "w", stdout);
    }

    int t = 1;
//    cin >> t;

    for (int test = 1; test <= t; test++) {
        Solve();
    }
    return 0;
}

Compilation message (stderr)

joioi.cpp: In function 'void Solve()':
joioi.cpp:80:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   80 |         int mid = l + r >> 1;
      |                   ~~^~~
joioi.cpp: In function 'int32_t main()':
joioi.cpp:90:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         freopen("JOI17_joioi.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
joioi.cpp:91:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |         freopen("JOI17_joioi.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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