Create 5725_summer_via.cpp

From http://blog.csdn.net/summer_via/article/details/51979297

HDOJ/5725_summer_via.cpp

@@ -0,0 +1,114 @@
+#include<iostream>
+#include<cstdio>
+#include<cstring>
+#include<cstdlib>
+#include<cmath>
+#include<algorithm>
+#include<map>
+#include<string>
+#include<queue>
+#include<vector>
+#include<list>
+//#pragma comment(linker,"/STACK:1024000000,1024000000")
+using namespace std;
+#define INF 0x3f3f3f3f
+int n,m;
+long long dp[1005][1005];
+long long dp2[505][505];
+char mp[1005][1005];
+//n*m的图，计算以（1，1）为起点到所有曼哈顿距离和
+long long get(long long n,long long m)
+{
+    return m*(m-1)*n/2+n*(n-1)*m/2;
+}
+//n*m的图，计算任意点到所有点的曼哈顿距离和
+long long get2(long long x,long long y)
+{
+    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));
+}
+int xx[1005],yy[1005],cnt2;
+int pr[1005],pc[1005];
+int main()
+{
+    int t;
+    scanf("%d",&t);
+    while(t--)
+    {
+        cnt2=0;
+        scanf("%d%d",&n,&m);
+        long long up=(long long)m*n*(m*n-1)*(m+n)/3,down=0;
+        int cnt=0;
+        memset(pr,-1,sizeof pr);
+        memset(pc,-1,sizeof pc);
+        getchar();
+        for(int i=0;i<n;i++)
+        {
+
+            gets(mp[i]);
+            for(int j=0;j<m;j++)
+            {
+                if(mp[i][j]=='G')
+                {
+                    pr[i]=j;
+                    pc[j]=i;
+                    up-=4ll*j*(m-j-1);//同行被阻断会在后面重复计算
+                    up-=4ll*i*(n-i-1);//同列类似
+                    up-=2*get2(i+1,j+1),cnt++;
+                    xx[cnt2]=i;
+                    yy[cnt2]=j;
+                    cnt2++;
+                }
+            }
+        }
+        //计算绕行路径和
+        int suml=0,sumr=0;
+        for(int i=0;i<n;i++)
+        {
+            if(pr[i]!=-1)
+            {
+                if(i==0||pr[i]>pr[i-1]) suml+=pr[i];
+                else suml=pr[i];
+                up+=4ll*suml*(m-pr[i]-1);
+            }
+            else suml=0;
+            if(pr[i]!=-1)
+            {
+                if(i==0||pr[i]<pr[i-1]) sumr+=m-pr[i]-1;
+                else sumr=m-pr[i]-1;
+                up+=4ll*sumr*pr[i];
+            }
+            else sumr=0;
+        }
+        int sumu=0,sumd=0;
+        for(int i=0;i<m;i++)
+        {
+            if(pc[i]!=-1)
+            {
+                if(i==0||pc[i]>pc[i-1]) sumu+=pc[i];
+                else sumu=pc[i];
+                up+=4ll*sumu*(n-pc[i]-1);
+            }
+            else sumu=0;
+            if(
+               pc[i]!=-1)
+            {
+                if(i==0||pc[i]<pc[i-1]) sumd+=n-pc[i]-1;
+                else sumd=n-pc[i]-1;
+                up+=4ll*sumd*pc[i];
+            }
+            else sumd=0;
+        }
+
+        for(int i=0;i<cnt2;i++)
+        {
+            for(int j=0;j<cnt2;j++)
+            {
+                up+=abs(xx[i]-xx[j])+abs(yy[i]-yy[j]);
+            }
+        }
+        down=(long long)(n*m-cnt)*(n*m-cnt);
+        double ans=(long double)up/down;
+        printf("%.4llf\n",ans);
+    }
+    return 0;
+}