bzoj 4008、4011、1499

全是扒题解，，，太弱了。。。

不乱BB了。

4008

 #include <bits/stdc++.h>
 #define LL long long
 #define lowbit(x) x&(-x)
 #define inf 0x3f3f3f3f
 #define eps 1e-5
 #define N 100005
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 int T;
 int n,r,d[];
 double p[];
 double f[][],pw[][];
 int main(int argc, char const *argv[])
 {
     T=ra();
     while (T--)
     {
         n=ra(); r=ra();
         memset(f,,sizeof(f));
         for (int i=; i<=n; i++)
         {
             scanf("%lf",&p[i]);
             d[i]=ra();
         }
         double ans=;
         for (int i=; i<=n; i++)
         {
             pw[i][]=;
             for (int j=; j<=r; j++) pw[i][j]=pw[i][j-]*(-p[i]);
         }
         f[][r]=;
         for (int i=; i<n; i++)
             for (int j=; j<=r; j++)
             {
                 f[i+][j]+=f[i][j]*pw[i+][j];
                 if (j->=)
                 {
                     f[i+][j-]+=f[i][j]*(-pw[i+][j]);
                     ans+=f[i][j]*(-pw[i+][j])*d[i+];
                 }
             }
         printf("%.10lf\n",ans);
     }
     return ;
 }

4011

 #include <bits/stdc++.h>
 #define LL long long
 #define lowbit(x) x&(-x)
 #define inf 0x3f3f3f3f
 #define eps 1e-5
 #define N 100005
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 const int mod=1e9+;
 LL ans=;
 int n,m,x,y,cnt;
 int head[],d[],b[];
 LL f[],ine[];
 vector<int> st;
 struct edge{
     int to,next;
 }e[];
 void insert(int x, int y)
 {
     e[++cnt].next=head[x]; e[cnt].to=y; head[x]=cnt;
 }
 void dp()
 {
     f[y]=ans;
     for (int i=; i<=n; i++) if (!d[i]) st.push_back(i);
     while (!st.empty())
     {
         int now=st.back(); st.pop_back();
         f[now]=f[now]*ine[b[now]]%mod;
         for (int i=head[now];i;i=e[i].next)
         {
             f[e[i].to]=(f[e[i].to]+f[now])%mod;
             d[e[i].to]--;
             if (!d[e[i].to]) st.push_back(e[i].to);
         }
     }
 }
 int main(int argc, char const *argv[])
 {
     n=ra(); m=ra(); x=ra(); y=ra();
     ine[]=;
     for (int i=; i<=m+; i++) ine[i]=(-ine[mod%i]*(mod/i)+mod)%mod;//??
     for (int i=; i<=m; i++)
     {
         int xx=ra(),yy=ra();
         insert(xx,yy);
         d[yy]++;
     }
     d[y]++;
     for (int i=; i<=n; i++) b[i]=d[i];
     for (int i=; i<=n; i++)
         ans=ans*d[i]%mod;
     d[y]--;
     if (y==) {printf("%lld\n",ans); return ;}
     dp();
     ans=(ans-f[x]+mod)%mod;
     printf("%lld\n",ans);
     return ;
 }

1499

 #include <bits/stdc++.h>
 #define LL long long
 #define lowbit(x) x&(-x)
 #define inf 0x3f3f3f3f
 #define eps 1e-5
 #define N 100005
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 char a[][];
 int f[][];
 int xx[]={,-,,,},yy[]={,,,-,};
 int q[],pos[],head,tail;
 int n,m,sx,sy,K,ans;
 void push(int now, int val)
 {
     if (val==-inf) return;
     while (val-now>q[tail] && head<=tail) tail--;
     q[++tail]=val-now;
     pos[tail]=now;
 }
 void dp(int p, int x, int y, int d, int T)
 {
     head=,tail=; int now=;
     while (x<=n && y<=m && x>= && y>=)
     {
         if (a[x][y]=='x') head=,tail=;
             else push(now,f[x][y]);
         while (now-pos[head]>T && head<=tail) head++;
         if (head<=tail) f[x][y]=q[head]+now;
             else f[x][y]=-inf;
         ans=max(ans,f[x][y]);
         x+=xx[d]; y+=yy[d];
         now++;
     }
 }
 int main(int argc, char const *argv[])
 {
     n=ra(); m=ra(); sx=ra(); sy=ra(); K=ra();
     for (int i=; i<=n; i++) scanf("%s",a[i]+);
     for (int i=; i<=n; i++)
         for (int j=; j<=m; j++)
             f[i][j]=-inf;
     f[sx][sy]=;
     for (int i=; i<=K; i++)
     {
         int x=ra(),y=ra(),d=ra();
         if (d==) for (int j=; j<=m; j++) dp(i,n,j,d,y-x+);
         if (d==) for (int j=; j<=m; j++) dp(i,,j,d,y-x+);
         if (d==) for (int j=; j<=n; j++) dp(i,j,m,d,y-x+);
         if (d==) for (int j=; j<=n; j++) dp(i,j,,d,y-x+);
     }
     printf("%d\n",ans);
     return ;
 }