70 lines
1.4 KiB
C++
70 lines
1.4 KiB
C++
#include<iostream>
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#include<cstring>
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using namespace std;
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const int maxn=110;
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int map[maxn][maxn],color[maxn][maxn];
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char s[maxn][maxn];
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int n,m,r,c,ans;
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void change()
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{
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int i,j,k,p;
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for(i=0;i<n;i++)
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{
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for(j=0;j<m;j++)
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{
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if(i+r<=n&&j+c<=m&&map[i][j]!=color[i][j])
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{
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for(k=i;k<i+r;k++)
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{
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for(p=j;p<j+c;p++)
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if(color[k][p])
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color[k][p]=0;
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else
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color[k][p]=1;
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}
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ans++;
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}
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}
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}
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}
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int judge()
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{
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int i,j,k;
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for(i=0;i<n;i++)
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{
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for(j=0;j<m;j++)
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{
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if(map[i][j]!=color[i][j])
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return 0;
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}
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}
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return 1;
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}
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int main(void)
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{
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int i,j;
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while(scanf("%d%d%d%d",&n,&m,&r,&c)!=EOF)
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{
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if(n==0&&m==0&&r==0&&c==0)
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break;
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memset(map,0,sizeof(map));
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memset(color,0,sizeof(color));
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memset(s,0,sizeof(s));
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ans=0;
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for(i=0;i<n;i++)
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{
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scanf("%s",s[i]);
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for(j=0;j<m;j++)
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{
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map[i][j]=s[i][j]-'0';
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}
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}
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change();
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if(judge())
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printf("%d\n",ans);
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else
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printf("-1\n");
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}
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return 0;
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}
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