题意与思路:主要参考了大佬的做法,大佬的做法,真的很奇妙,真不知道我何时能达到如此水平。。。
#include<bits/stdc++.h>
using namespace std;
const int maxn=2e5+1;
typedef long long ll;
ll p[maxn],a[maxn];
struct node{
int l,r;
ll minn,lazy;
}tree[maxn<<3];
void pushup(int x)
{
if(tree[x].lazy)
{
tree[x<<1].minn+=tree[x].lazy;
tree[x<<1|1].minn+=tree[x].lazy;
tree[x<<1].lazy+=tree[x].lazy;
tree[x<<1|1].lazy+=tree[x].lazy;
tree[x].lazy=0;
}
}
void build(int l,int r,int x)
{
tree[x].l=l;tree[x].r=r;
if(l==r)
{
tree[x].minn=tree[x].lazy=0;
return ;
}
int mid=(l+r)>>1;
build(l,mid,x<<1);
build(mid+1,r,x<<1|1);
tree[x].minn=min(tree[x<<1].minn,tree[x<<1|1].minn);
}
void update(int l,int r,int v,int x)
{
if(l<=tree[x].l&&tree[x].r<=r)
{
tree[x].lazy+=v;
tree[x].minn+=v;
return ;
}
pushup(x);
int mid=(tree[x].l+tree[x].r)>>1;
if(l<=mid) update(l,r,v,x<<1);
if(r>mid) update(l,r,v,x<<1|1);
tree[x].minn=min(tree[x<<1].minn,tree[x<<1|1].minn);
}
int main()
{
int n;
scanf("%d",&n);
for(int i=1;i<=n;++i) scanf("%lld",&p[i]);
build(1,n,1);
for(int i=1;i<=n;++i)
scanf("%lld",&a[i]),update(p[i]+1,n,a[i],1);
ll ans=min(a[1],a[n]);
for(int i=1;i<n;++i) {
update(p[i]+1,n,-a[i],1);//恢复原状
update(1,p[i]-1,a[i],1);//计算第一集合
ans=min(ans,tree[1].minn);
}
printf("%lld\n",ans);
}