#include <bits/stdc++.h>
using namespace std;
const int maxn = 2010;
int a[maxn][maxn];
int L[maxn][maxn][2];
int R[maxn][maxn][2];
int D[maxn][maxn][2];
int U[maxn][maxn][2];
int main() {
int n, m;
scanf("%d%d", &n, &m);
int mn = 1e9, mx = 1;
for (int i = 0; i < n; ++i) {
for (int j = 0; j < m; ++j) {
scanf("%d", a[i]+j);
mn = min(mn, a[i][j]);
mx = max(mx, a[i][j]);
}
}
for (int i = 0; i < n; ++i) {
L[i][0][0] = L[i][0][1] = a[i][0];
for (int j = 1; j < m; ++j) {
L[i][j][0] = min(L[i][j-1][0], a[i][j]);
L[i][j][1] = max(L[i][j-1][1], a[i][j]);
}
R[i][m-1][0] = R[i][m-1][1] = a[i][m-1];
for (int j = m-2; j >= 0; --j) {
R[i][j][0] = min(R[i][j+1][0], a[i][j]);
R[i][j][1] = max(R[i][j+1][1], a[i][j]);
}
}
for (int j = 0; j < m; ++j) {
U[0][j][0] = U[0][j][1] = a[0][j];
for (int i = 1; i < n; ++i) {
U[i][j][0] = min(U[i-1][j][0], a[i][j]);
U[i][j][1] = max(U[i-1][j][1], a[i][j]);
}
D[n-1][j][0] = D[n-1][j][1] = a[n-1][j];
for (int i = n-2; i >= 0; --i) {
D[i][j][0] = min(D[i+1][j][0], a[i][j]);
D[i][j][1] = max(D[i+1][j][1], a[i][j]);
}
}
auto getL = [&](int x) {
int mi = 1e9, ma = 1;
for (int i = 0, t = m-1; i < n; ++i) {
int lo = 0, hi = m-1;
while (lo < hi) {
int mid = lo + (hi - lo + 1) / 2;
if (L[i][mid][1] - mn <= x) lo = mid;
else hi = mid-1;
}
if (L[i][lo][1] - mn > x) lo -= 1;
t = min(t, lo);
if (t + 1 < m) {
mi = min(mi, R[i][t+1][0]);
ma = max(ma, R[i][t+1][1]);
}
}
return ma - mi <= x;
};
auto getR = [&](int x) {
int mi = 1e9, ma = 1;
for (int i = 0, t = 0; i < n; ++i) {
int lo = 0, hi = m-1;
while (lo < hi) {
int mid = lo + (hi - lo) / 2;
if (R[i][mid][1] - mn > x) lo = mid+1;
else hi = mid;
}
if (R[i][lo][1] - mn > x) lo += 1;
t = max(t, lo);
if (lo > 0) {
mi = min(mi, L[i][t-1][0]);
ma = max(ma, L[i][t-1][1]);
}
}
return ma - mi <= x;
};
auto getU = [&](int x) {
int mi = 1e9, ma = 1;
for (int i = 0, t = n-1; i < m; ++i) {
int lo = 0, hi = n-1;
while (lo < hi) {
int mid = lo + (hi - lo + 1) / 2;
if (U[mid][i][1] - mn <= x) lo = mid;
else hi = mid-1;
}
if (U[lo][i][1] - mn > x) lo -= 1;
t = min(t, lo);
if (t + 1 < n) {
mi = min(mi, D[t+1][i][0]);
ma = max(ma, D[t+1][i][1]);
}
}
return ma - mi <= x;
};
auto getD = [&](int x) {
int mi = 1e9, ma = 1;
for (int i = 0, t = 0; i < m; ++i) {
int lo = 0, hi = n-1;
while (lo < hi) {
int mid = lo + (hi - lo) / 2;
if (D[mid][i][1] - mn > x) lo = mid+1;
else hi = mid;
}
if (D[lo][i][1] - mn > x) lo += 1;
t = max(t, lo);
if (t > 0) {
mi = min(mi, U[t-1][i][0]);
ma = max(ma, U[t-1][i][1]);
}
}
return ma - mi <= x;
};
auto p = [&](int x) {
if (getL(x)) return 1;
if (getR(x)) return 1;
if (getD(x)) return 1;
if (getU(x)) return 1;
return 0;
};
int lo = 0, hi = mx - mn;
while (lo < hi) {
int mid = lo + (hi - lo) / 2;
if (!p(mid)) lo = mid+1;
else hi = mid;
}
printf("%d\n", lo);
return 0;
}
Compilation message
joioi.cpp: In function 'int main()':
joioi.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
13 | scanf("%d%d", &n, &m);
| ~~~~~^~~~~~~~~~~~~~~~
joioi.cpp:17:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
17 | scanf("%d", a[i]+j);
| ~~~~~^~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
492 KB |
Output is correct |
| 2 |
Correct |
1 ms |
492 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
492 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
492 KB |
Output is correct |
| 2 |
Correct |
1 ms |
492 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
492 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
492 KB |
Output is correct |
| 2 |
Correct |
1 ms |
492 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
492 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
