#include <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define f first
#define s second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pb push_back
#define epb emplace_back
using namespace std;
const int nmax = 2005;
pii dp[nmax][nmax];
int last[nmax];
int mnx, mny;
int MN;
int n, m;
const int inf = 1e9 + 1;
int mn[nmax][nmax], mx[nmax][nmax];
int a[nmax][nmax];
void fil(){
for(int i = 1; i <= n; i++){
mn[i][m + 1] = inf;
mx[i][m + 1] = -inf;
for(int j = m; j >= 1; j--)
mx[i][j] = max(a[i][j], mx[i][j + 1]),
mn[i][j] = min(a[i][j], mn[i][j + 1]);
}
}
bool check(int X){
for(int i = 0; i <= n; i++){
for(int j = 0; j <= m; j++)
dp[i][j] = {inf, -inf};
if(i == 0) last[i] = m;
else last[i] = 0;
}
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
if(a[i][j] > MN + X) break;
last[i]++;
}
}
last[1] = min(last[1], m - 1);
for(int i= 1; i <= n; i++){
for(int j = 0; j <= last[i]; j++){
if(i == mnx && j < mny) {
dp[i][j] = {-inf, inf};
continue;
}
int u = min(j, last[i - 1]);
dp[i][j].f = min(dp[i - 1][u].f, mn[i][j + 1]);
dp[i][j].s = max(dp[i - 1][u].s, mx[i][j + 1]);
}
for(int j = last[i] + 1; j <= m; j++)
dp[i][j] = {-inf, inf};
}
for(int j = 1; j <= m; j++){
if(dp[n][j].s == -inf) continue;
if(dp[n][j].s - dp[n][j].f <= X) return true;
}
for(int i = 0; i <= n; i++){
for(int j = 0; j <= m; j++)
dp[i][j] = {inf, -inf};
}
for(int i = 1; i <= n; i++){
last[i] = 0;
for(int j = 1; j <= m; j++){
if(a[i][j] > MN + X) break;
last[i]++;
}
}
for(int i= 1; i <= n; i++){
for(int j = 0; j <= last[i]; j++){
if(i == mnx && j < mny) {
dp[i][j] = {-inf, inf};
continue;
}
int u = max(j, last[i - 1]);
dp[i][j].f = min(dp[i - 1][u].f, mn[i][j + 1]);
dp[i][j].s = max(dp[i - 1][u].s, mx[i][j + 1]);
}
for(int j = last[i] + 1; j <= m; j++)
dp[i][j] = {-inf, inf};
}
for(int j = 0; j < m; j++){
if(dp[n][j].s == -inf) continue;
if(dp[n][j].s - dp[n][j].f <= X) return true;
}
return false;
}
int main(){
cin >> n >> m;
MN = inf;
for(int i = 1; i <= n; i++){
for(int j= 1; j <= m; j++){
cin >> a[i][j];
if(a[i][j] < MN)
MN = a[i][j], mnx = i, mny = j;
}
}
fil();
int l = 0, r = 1e9+ 1;
while(l + 1 < r){
int mid = (l + r) / 2;
if(check(mid)) r = mid;
else l = mid;
}
//cout << r;
for(int i = 1 ;i <= n; i++){
for(int j = 1; j <= m - j + 1; ++j)
swap(a[i][j], a[i][m - j + 1]);
}
mny = m - mny + 1;
int ans = r;
l = 0, r = 1e9 +1;
fil();
while(l + 1 < r){
int mid = (l + r) / 2;
if(check(mid)) r = mid;
else l = mid;
}
cout << min(ans, r);
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Incorrect |
1 ms |
436 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Incorrect |
1 ms |
436 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Incorrect |
1 ms |
436 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |