首页 > 代码库 > BZOJ 2216 Lightning Conductor

BZOJ 2216 Lightning Conductor

决策单调。整体二分。

#include<iostream>#include<cstdio>#include<cmath>#include<cstring>#include<algorithm>#define maxn 500500using namespace std;int n,a[maxn],f[maxn],g[maxn];void dp1(int left,int right,int l,int r){    if (left>right) return;    int mid=left+right>>1;    int pos;double mx=0;    for (int i=l;i<=r && i<=mid;i++)    {        if ((double)a[i]+sqrt(mid-i)>mx)        {            mx=(double)a[i]+sqrt(mid-i);            pos=i;        }    }    f[mid]=a[pos]+ceil(sqrt(mid-pos));    dp1(left,mid-1,l,pos);dp1(mid+1,right,pos,r);}void dp2(int left,int right,int l,int r){    if (left>right) return;    int mid=left+right>>1;    int pos;double mx=0;    for (int i=r;i>=l && i>=mid;i--)    {        if ((double)a[i]+sqrt(i-mid)>mx)        {            mx=(double)a[i]+sqrt(i-mid);            pos=i;        }    }    g[mid]=a[pos]+ceil(sqrt(pos-mid));    dp2(left,mid-1,l,pos);dp2(mid+1,right,pos,r);}int main(){    scanf("%d",&n);    for (int i=1;i<=n;i++)        scanf("%d",&a[i]);    dp1(1,n,1,n);dp2(1,n,1,n);    for (int i=1;i<=n;i++)        printf("%d\n",max(f[i],g[i])-a[i]);    return 0;}

 

BZOJ 2216 Lightning Conductor