BZOJ 2459 [BeiJing2011]神秘好人

题意：2行n列网格图，边有边权，支持

1.修改边权

2.询问两点间最短路

Sol:

身经百战之后，已经没有什么好怕的了，3行n列我也写给你看= =

把Traffic的bool数组改成int维护长度就行了

也是注意绕路情况，合并时耿直的讨论一下

Code:

#include<bits/stdc++.h>
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define debug(x) cout<<#x<<"="<<x<<endl
using namespace std;
const int maxn = 100009;
int n,m;
struct sg_tree
{
int dis[2][2],ll,rr;
int up,down;
void cover(int x)
{
dis[0][0]=dis[1][1]=0;
dis[0][1]=dis[1][0]=x;
ll=rr=x;up=down=0;
}
}node[maxn<<2];
typedef sg_tree Block;

inline int read()
{
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}

Block Merge(Block L,Block R,int up,int down)
{
Block now;
now.up=up;now.down=down;
now.ll=min(L.ll,L.dis[0][0]+R.ll+L.dis[1][1]+up+down);
now.rr=min(R.rr,R.dis[0][0]+L.rr+R.dis[1][1]+up+down);
now.dis[0][0]=min(L.dis[0][0]+down+R.dis[0][0],L.dis[0][1]+up+R.dis[1][0]);
now.dis[0][1]=min(L.dis[0][0]+down+R.dis[0][1],L.dis[0][1]+up+R.dis[1][1]);
now.dis[1][0]=min(L.dis[1][0]+down+R.dis[0][0],L.dis[1][1]+up+R.dis[1][0]);
now.dis[1][1]=min(L.dis[1][0]+down+R.dis[0][1],L.dis[1][1]+up+R.dis[1][1]);
return now;
}
void Modify(int l,int r,int rt,int left,int right,int delta,int pos)
{
int mid=(l+r)>>1;
if(right<=mid) Modify(lson,left,right,delta,pos);
else if(left>mid) Modify(rson,left,right,delta,pos);
else{if(pos) node[rt].up=delta;else node[rt].down=delta;}
node[rt]=Merge(node[rt<<1],node[rt<<1|1],node[rt].up,node[rt].down);
}
void Insert(int l,int r,int rt,int pos,int delta)
{
if(l==r)
{
node[rt].cover(delta);
return ;
}int mid=(l+r)>>1;
if(pos<=mid) Insert(lson,pos,delta);
else Insert(rson,pos,delta);
node[rt]=Merge(node[rt<<1],node[rt<<1|1],node[rt].up,node[rt].down);
}
Block Query(int l,int r,int rt,int left,int right)
{
if(l==left&&right==r) return node[rt];
int mid=(l+r)>>1;
if(right<=mid) return Query(lson,left,right);
else if(left>mid) return Query(rson,left,right);
else return Merge(Query(lson,left,mid),Query(rson,mid+1,right),node[rt].up,node[rt].down);
}

int main()
{
n=read();
for(int i=1;i<n;i++) Modify(1,n,1,i,i+1,read(),1);
for(int i=1;i<=n;i++) Insert(1,n,1,i,read());
for(int i=1;i<n;i++) Modify(1,n,1,i,i+1,read(),0);
m=read();
while(m--)
{
int opt=read();
if(opt==0)
{
int pos=read(),idx=read(),val=read();
if(pos==0) Modify(1,n,1,idx,idx+1,val,1);
if(pos==1) Insert(1,n,1,idx,val);
if(pos==2) Modify(1,n,1,idx,idx+1,val,0);
}
else
{
int x=read(),y=read();if(x>y) swap(x,y);
int l=(x+1)>>1,r=(y+1)>>1;x=x&1;y=y&1;
Block L=Query(1,n,1,1,l),Mid=Query(1,n,1,l,r),R=Query(1,n,1,r,n);
int ans=Mid.dis[x][y];
ans=min(ans,L.rr+Mid.dis[x^1][y]);
ans=min(ans,R.ll+Mid.dis[x][y^1]);
ans=min(ans,L.rr+Mid.dis[x^1][y^1]+R.ll);
printf("%d\n",ans);
}
}
return 0;
}