传送门:http://acm.hdu.edu.cn/contests/contest_showproblem.php?pid=1002&cid=589
思路:对于每个人,向右二分判断能组成group最远的人,用ST表维护最大最小值,判断时只要看最大最小只差是否小于k即可
CYY的代码
#include<cmath> #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> using namespace std; typedef long long int64; const double eps=1e-7; const int maxn=100015,maxk=20; int n,m,k,a[maxn];int64 ans; int bin[maxk],fmx[maxk][maxn],fmn[maxk][maxn]; void read(int &x){ char ch; for (ch=getchar();!isdigit(ch);ch=getchar()); for (x=0;isdigit(ch);ch=getchar()) x=x*10+ch-'0'; } void init(){ read(n);read(m); for (int i=1;i<=n;++i) read(a[i]); } void prepare(){ k=floor(log2(n)+eps); for (int i=1;i<=n;++i) fmx[0][i]=fmn[0][i]=a[i]; for (int i=1;i<=k;++i) for (int j=bin[i];j<=n;++j){ fmx[i][j]=max(fmx[i-1][j],fmx[i-1][j-bin[i-1]]); fmn[i][j]=min(fmn[i-1][j],fmn[i-1][j-bin[i-1]]); } } int qmax(int l,int r){ int q=floor(log2(r-l+1)+eps); return max(fmx[q][r],fmx[q][l+bin[q]-1]); } int qmin(int l,int r){ int q=floor(log2(r-l+1)+eps); return min(fmn[q][r],fmn[q][l+bin[q]-1]); } int query(int a,int b){ int l=a,r=b,res; while (l<=r){ int mid=(l+r)>>1; if (qmax(mid,b)-qmin(mid,b)<m) r=(res=mid)-1; else l=mid+1; } return res; } void work(){ prepare(); ans=0;for (int i=1;i<=n;++i) ans+=(i-query(1,i)+1); printf("%I64d ",ans); } int main(){ int cases;scanf("%d",&cases); bin[0]=1;for (int i=1;i<maxk;++i) bin[i]=bin[i-1]<<1; while (cases--){init();work();} return 0; }