88 lines
2.7 KiB
C++
88 lines
2.7 KiB
C++
#include <stdio.h>
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#include <cstring>
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#include <algorithm>
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using namespace std;
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#define inf 100000
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int n,m;
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int a[101][10010];
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int r[101][10010],c[101][10010];
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int que[10010][2],p,q;
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inline int max(int x,int y){return x<y?y:x;}
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inline int min(int x,int y){return x<y?x:y;}
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int main()
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{
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while(scanf("%d%d",&n,&m)!=EOF)
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{
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if (n==0 && m==0) return 0;
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for (int i=1;i<=n;i++)
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for (int j=1;j<=m;j++)
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{
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scanf("%d",&a[i][j]);
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r[i][j]=c[i][j]=inf;
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}
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int ans=-1;
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while(1)
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{
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for (int i=1;i<=n;i++)
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for (int j=1;j<=m;j++)
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r[i][j]=c[i][j]=inf;
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for (int i=1;i<=n;i++)
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{
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p=1;q=0;
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for (int j=1;j<=m;j++)
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{
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while(p<=q && a[i][j]+j-1>=que[q][1]) q--;
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que[++q][0]=j;que[q][1]=a[i][j]+j-1;
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while(p<=q && que[q][1]<j) q--;
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if (p<=q)
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r[i][j]=j-que[q][0]+1;
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}
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p=1;q=0;
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for (int j=m;j>=1;j--)
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{
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while(p<=q && j-a[i][j]+1<=que[q][1]) q--;
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que[++q][0]=j;que[q][1]=j-a[i][j]+1;
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while(p<=q && que[q][1]>j) q--;
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if (p<=q)
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r[i][j]=min(r[i][j], que[q][0]-j+1);
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}
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}
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for (int j=1;j<=m;j++)
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{
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p=1;q=0;
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for (int i=1;i<=n;i++)
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{
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while(p<=q && a[i][j]+i-1>=que[q][1]) q--;
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que[++q][0]=i;que[q][1]=a[i][j]+i-1;
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while(p<=q && que[q][1]<i) q--;
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if (p<=q) c[i][j]=i-que[q][0]+1;
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}
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p=1;q=0;
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for (int i=n;i>=1;i--)
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{
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while(p<=q && i-a[i][j]+1<=que[q][1]) q--;
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que[++q][0]=i;que[q][1]=i-a[i][j]+1;
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while(p<=q && que[q][1]>i) q--;
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if (p<=q) c[i][j]=min(c[i][j], que[q][0]-i+1);
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}
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}
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int tmp=0;
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for (int i=1;i<=n;i++)
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for (int j=1;j<=m;j++)
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{
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tmp=max(tmp,max(c[i][j],r[i][j]));
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}
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if (tmp==ans) break;
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ans=tmp;
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for (int i=1;i<=n;i++)
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for (int j=1;j<=m;j++)
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{
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a[i][j]=(a[i][j]<tmp?0:a[i][j]);
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}
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}
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if (ans<inf) printf("%d\n",ans);
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else printf("NO ANSWER!\n");
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}
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return 0;
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}
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