| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 518540 | Giantpizzahead | The Kingdom of JOIOI (JOI17_joioi) | Java | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
/*
Solution:
Runtime:
*/
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define sz(x) ((int) x.size())
#define all(x) x.begin(), x.end()
#define debug if (false) cerr
using ll = long long;
const int INF = 1e9+7;
const int MAXN = 2005;
int H, W, minV = INF, maxV = -INF;
int A[MAXN][MAXN], newA[MAXN][MAXN];
struct Loc {
int i, j, c;
bool operator<(const Loc& o) const {
return c > o.c;
}
};
vector<Loc> locs;
set<pair<int, int>> boundL, boundR;
int getAns() {
locs.clear();
boundL.clear();
boundR.clear();
rep(i, 0, H) rep(j, 0, W) locs.push_back({i, j, max(maxV - A[i][j], A[i][j] - minV)});
sort(all(locs));
// Place into regions until invalid
boundL.insert({H, -1});
boundR.insert({-1, W});
int ans = INF;
for (Loc& l : locs) {
int i = l.i, j = l.j;
debug << endl << "place A[" << i << "][" << j << "] = " << A[i][j] << endl;
if (maxV - A[i][j] == l.c) {
// Should go along with min (left) region
auto ptr = prev(boundR.lower_bound({i, INF}));
if (ptr->second <= j) {
// Does not work
ans = l.c;
break;
}
// This works; update left region bound
ptr = boundL.lower_bound({i, -1});
if (ptr->second < j) {
// Update the bound
while (true) {
ptr = boundL.lower_bound({i, INF});
if (ptr == boundL.begin()) break;
ptr = prev(ptr);
if (ptr->second > j) break;
boundL.erase(ptr);
}
// Place new bound
boundL.insert({i, j});
}
debug << "left" << endl;
} else {
// Should go along with max (right) region
auto ptr = boundL.lower_bound({i, -1});
if (ptr->second >= j) {
// Does not work
ans = l.c;
break;
}
// This works; update right region bound
ptr = prev(boundR.lower_bound({i, INF}));
if (ptr->second > j) {
// Update the bound
while (true) {
ptr = boundR.lower_bound({i, -1});
if (ptr == boundR.end() || ptr->second < j) break;
boundR.erase(ptr);
}
// Place new bound
boundR.insert({i, j});
}
debug << "right" << endl;
}
ans = min(maxV - A[i][j], A[i][j] - minV);
// Debug boundaries
vector<vector<char>> test(H, vector<char>(W, '.'));
for (auto& p : boundL) {
if (p.second == -1) continue;
test[p.first][p.second] = '1';
}
for (auto& p : boundR) {
if (p.first == -1) continue;
test[p.first][p.second] = '2';
}
rep(i, 0, H) rep(j, 0, W) debug << test[i][j] << " \n"[j==W-1];
}
debug << "ans " << ans << endl;
return ans;
}
void solve() {
cin >> H >> W;
rep(i, 0, H) rep(j, 0, W) {
cin >> A[i][j];
minV = min(A[i][j], minV);
maxV = max(A[i][j], maxV);
}
// Try all rotations and flips
int ans = maxV - minV;
rep(d, 0, 8) {
debug << endl;
rep(i, 0, H) rep(j, 0, W) debug << A[i][j] << " \n"[j==W-1];
int tempAns = getAns();
// cout << tempAns << '\n';
ans = min(tempAns, ans);
if (d != 3) {
// Rotate board
// (i, j) -> (j, [new W]-1-i)
rep(i, 0, H) rep(j, 0, W) newA[j][H-1-i] = A[i][j];
swap(H, W);
rep(i, 0, H) rep(j, 0, W) A[i][j] = newA[i][j];
} else {
// Flip board
// (i, j) -> (H-1-i, j)
rep(i, 0, H) rep(j, 0, W) newA[H-1-i][j] = A[i][j];
rep(i, 0, H) rep(j, 0, W) A[i][j] = newA[i][j];
}
}
cout << ans << '\n';
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}