Submission #855867

#	Time	Username	Problem	Language	Result	Execution time	Memory
855867		abcvuitunggio	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	712 ms	54972 KiB

joioi

#include <bits/stdc++.h>
using namespace std;
int h,w,a[2006][2006],mn[2006][2],mx[2006][2],tmp[2006],lo=1e9,hi;
bool check(int x){
    for (int i=1;i<=h;i++){
        mx[i][0]=mx[i][1]=-1;
        mn[i][0]=mn[i][1]=1e9;
        for (int j=1;j<=w;j++){
            if (a[i][j]>lo+x&&a[i][j]<hi-x)
                return false;
            if (a[i][j]>=hi-x&&a[i][j]<=lo+x)
                continue;
            int val=(a[i][j]>=hi-x);
            mx[i][val]=max(mx[i][val],j);
            mn[i][val]=min(mn[i][val],j);
        }
    }
    int ch=4;
    tmp[h+1]=0;
    for (int k=0;k<2;k++){
        for (int i=1;i<=h;i++)
            tmp[i]=max(tmp[i-1],mx[i][k]);
        int cur=w+1;
        for (int i=h;i>=1;i--){
            cur=min(cur,mn[i][k^1]);
            if (cur<=tmp[i]){
                ch--;
                break;
            }
        }
        for (int i=h;i>=1;i--)
            tmp[i]=max(tmp[i+1],mx[i][k]);
        cur=w+1;
        for (int i=1;i<=h;i++){
            cur=min(cur,mn[i][k^1]);
            if (cur<=tmp[i]){
                ch--;
                break;
            }
        }
    }
    return ch;
}
int main(){
    ios_base::sync_with_stdio(NULL);cin.tie(nullptr);
    cin >> h >> w;
    for (int i=1;i<=h;i++)
        for (int j=1;j<=w;j++){
            cin >> a[i][j];
            lo=min(lo,a[i][j]);
            hi=max(hi,a[i][j]);
        }
    int l=0,r=1e9,kq=-1;
    while (l<=r){
        int mid=(l+r)>>1;
        if (check(mid)){
            kq=mid;
            r=mid-1;
        }
        else
            l=mid+1;
    }
    cout << kq;
}

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