57 lines
1.1 KiB
C++
57 lines
1.1 KiB
C++
#include <iostream>
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#include <cstdio>
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#include <cstring>
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#include <algorithm>
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#define Max(a,b) a>b?a:b
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using namespace std;
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int n;
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int dp[1111],map[1111][1111];
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struct node
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{
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int x1,x2,y1,y2;
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}s[1111];
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int dfs(int x)
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{
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int i,j,k,l;
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if(dp[x])return dp[x];
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for(i=0;i<n;i++)
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if(map[x][i])
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{
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dp[x]=Max(dp[x],dfs(i)+1);
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}
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dp[x]=Max(dp[x],1);
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return dp[x];
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}
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int main (void)
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{
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int i,j,k,l,x1,x2,y1,y2,sum;
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while(scanf("%d",&n)!=EOF&&n)
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{
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for(i=0;i<n;i++)
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{
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scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
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s[i].x1=x1;
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s[i].x2=x2;
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s[i].y1=y1;
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s[i].y2=y2;
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}
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memset(map,0,sizeof(map));
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memset(dp,0,sizeof(dp));
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for(i=0;i<n;i++)
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for(j=0;j<n;j++)
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{
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if(s[i].x2<s[j].x1&&s[i].y2<s[j].y1)
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{
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map[i][j]=1;
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}
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}
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sum=0;
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for(i=0;i<n;i++)
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{
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sum=Max(sum,dfs(i));
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}
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printf("%d\n",sum);
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}
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return 0;
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}
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