Submission #143405

#	Time	Username	Problem	Language	Result	Execution time	Memory
143405		osaaateiasavtnl	The Kingdom of JOIOI (JOI17_joioi)	C++14	100 / 100	2584 ms	133528 KiB

joioi

#include<bits/stdc++.h>
using namespace std;
#define int long long 
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcount
const int N = 2007, INF = 1e9 + 7;
int n, m, mn = INF, a[N][N], r[N];
int suffmn[N][N], suffmx[N][N];
bool check_(int mid) {
    for (int i = 0; i < n; ++i) {
        suffmn[i][m] = INF; for (int j = m - 1; j >= 0; --j) suffmn[i][j] = min(suffmn[i][j + 1], a[i][j]);
        suffmx[i][m] = -INF; for (int j = m - 1; j >= 0; --j) suffmx[i][j] = max(suffmx[i][j + 1], a[i][j]);
    }
    int mx = mn + mid;
    for (int i = 0; i < n; ++i) { r[i] = 0; while (r[i] < m && a[i][r[i]] <= mx) ++r[i]; }   
    int MN, MX, c;
    c = m; MN = INF; MX = -INF;
    for (int i = 0; i < n; ++i) { c = min(c, r[i]); MN = min(MN, suffmn[i][c]); MX = max(MX, suffmx[i][c]); }
    if (MX - MN <= mid) return 1;
    c = m; MN = INF; MX = -INF;
    for (int i = n - 1; i >= 0; --i) { c = min(c, r[i]); MN = min(MN, suffmn[i][c]); MX = max(MX, suffmx[i][c]); }
    if (MX - MN <= mid) return 1;
    return 0;
}
void kek() {
    for (int i = 0; i < n; ++i) for (int j = 0; j < m / 2; ++j) swap(a[i][j], a[i][m - 1 - j]);
}
bool check(int mid) {
    if (check_(mid)) return 1;
    kek(); bool ans = check_(mid); kek();
    return ans;
}
signed main() {
    #ifdef HOME
    freopen("input.txt", "r", stdin);
    #else
    ios_base::sync_with_stdio(0); cin.tie(0);
    #endif
    cin >> n >> m;
    for (int i = 0; i < n; ++i) for (int j = 0; j < m; ++j) { cin >> a[i][j]; mn = min(mn, a[i][j]); }
    int l = -1, r = INF;
    while (l < r - 1) { int mid = (l + r) >> 1; if (check(mid)) r = mid; else l = mid; }
    cout << r << '\n';
}   

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