mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
115 lines
2.9 KiB
C++
115 lines
2.9 KiB
C++
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#include<iostream>
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#include<cstdio>
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#include<cstring>
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#include<cstdlib>
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#include<cmath>
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#include<algorithm>
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#include<map>
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#include<string>
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#include<queue>
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#include<vector>
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#include<list>
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//#pragma comment(linker,"/STACK:1024000000,1024000000")
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using namespace std;
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#define INF 0x3f3f3f3f
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int n,m;
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long long dp[1005][1005];
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long long dp2[505][505];
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char mp[1005][1005];
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//n*m的图，计算以（1，1）为起点到所有曼哈顿距离和
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long long get(long long n,long long m)
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{
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return m*(m-1)*n/2+n*(n-1)*m/2;
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}
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//n*m的图，计算任意点到所有点的曼哈顿距离和
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long long get2(long long x,long long y)
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{
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return get(x,y)+get(n-x+1,y)+get(x,m-y+1)+get(n-x+1,m-y+1)-(get(1,x)+get(1,y)+get(1,n-x+1)+get(1,m-y+1));
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}
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int xx[1005],yy[1005],cnt2;
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int pr[1005],pc[1005];
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int main()
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{
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int t;
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scanf("%d",&t);
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while(t--)
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{
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cnt2=0;
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scanf("%d%d",&n,&m);
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long long up=(long long)m*n*(m*n-1)*(m+n)/3,down=0;
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int cnt=0;
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memset(pr,-1,sizeof pr);
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memset(pc,-1,sizeof pc);
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getchar();
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for(int i=0;i<n;i++)
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{
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gets(mp[i]);
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for(int j=0;j<m;j++)
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{
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if(mp[i][j]=='G')
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{
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pr[i]=j;
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pc[j]=i;
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up-=4ll*j*(m-j-1);//同行被阻断会在后面重复计算
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up-=4ll*i*(n-i-1);//同列类似
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up-=2*get2(i+1,j+1),cnt++;
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xx[cnt2]=i;
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yy[cnt2]=j;
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cnt2++;
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}
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}
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}
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//计算绕行路径和
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int suml=0,sumr=0;
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for(int i=0;i<n;i++)
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{
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if(pr[i]!=-1)
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{
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if(i==0||pr[i]>pr[i-1]) suml+=pr[i];
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else suml=pr[i];
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up+=4ll*suml*(m-pr[i]-1);
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}
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else suml=0;
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if(pr[i]!=-1)
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{
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if(i==0||pr[i]<pr[i-1]) sumr+=m-pr[i]-1;
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else sumr=m-pr[i]-1;
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up+=4ll*sumr*pr[i];
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}
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else sumr=0;
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}
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int sumu=0,sumd=0;
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for(int i=0;i<m;i++)
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{
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if(pc[i]!=-1)
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{
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if(i==0||pc[i]>pc[i-1]) sumu+=pc[i];
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else sumu=pc[i];
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up+=4ll*sumu*(n-pc[i]-1);
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}
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else sumu=0;
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if(
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pc[i]!=-1)
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{
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if(i==0||pc[i]<pc[i-1]) sumd+=n-pc[i]-1;
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else sumd=n-pc[i]-1;
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up+=4ll*sumd*pc[i];
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}
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else sumd=0;
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}
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for(int i=0;i<cnt2;i++)
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{
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for(int j=0;j<cnt2;j++)
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{
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up+=abs(xx[i]-xx[j])+abs(yy[i]-yy[j]);
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}
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}
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down=(long long)(n*m-cnt)*(n*m-cnt);
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double ans=(long double)up/down;
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printf("%.4llf\n",ans);
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}
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return 0;
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}
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