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我現(xiàn)在才知道原來樹狀數(shù)組也叫分塊......

#include<cmath> #include<cstdio> #include<cctype> #include<iostream> #include<algorithm> using namespace std;typedef long long LL; int L[401],R[401],n,q,l,r,opt,x,pos[100010],t; double d,a[100010],sum[401],add[401],sumaf[401]; inline long long read() {char c;int d=1;long long f=0;while(c=getchar(),!isdigit(c))if(c==45)d=-1;f=(f<<3)+(f<<1)+c-48;while(c=getchar(),isdigit(c)) f=(f<<3)+(f<<1)+c-48;return d*f; } inline void write(register long long x) {if(x<0)putchar(45),x=-x;if(x>9)write(x/10);putchar(x%10+48);return; } double sqr(double x){return x*x;} void Add(register int l,register int r,double x) {int pl=pos[l],pr=pos[r];if(pl==pr){for(register int i=l;i<=r;i++) sumaf[pl]+=2*a[i]*x+sqr(x),a[i]+=x,sum[pl]+=x;return;}for(register int i=l;i<=R[pl];i++) sumaf[pl]+=2*a[i]*x+sqr(x),a[i]+=x,sum[pl]+=x;for(register int i=L[pr];i<=r;i++) sumaf[pr]+=2*a[i]*x+sqr(x),a[i]+=x,sum[pr]+=x;for(register int i=pl+1;i<pr;i++) add[i]+=x;return; } double ask(register int l,register int r) {int pl=pos[l],pr=pos[r],len=r-l+1;double ans=0;if(pl==pr){for(register int i=l;i<=r;i++) ans+=a[i]+add[pl];return ans/1.0/len;}else{for(register int i=l;i<=R[pl];i++) ans+=a[i]+add[pl];for(register int i=L[pr];i<=r;i++) ans+=a[i]+add[pr];for(register int i=pl+1;i<pr;i++) ans+=sum[i]+add[i]*t;return ans/1.0/len;} } double askfc(register int l,register int r) {int len=r-l+1,pl=pos[l],pr=pos[r];double ave=0,ans=0,answer=0;if(pl==pr){for(register int i=l;i<=r;i++) ave+=a[i]+add[pl],ans+=sqr(a[i]+add[pl]);return ans/len-sqr(ave/len);}for(register int i=l;i<=R[pl];i++) ave+=a[i]+add[pl],ans+=sqr(a[i]+add[pl]);for(register int i=L[pr];i<=r;i++) ave+=a[i]+add[pr],ans+=sqr(a[i]+add[pr]);for(register int i=pl+1;i<pr;i++) ave+=sum[i]+add[i]*t,ans+=sumaf[i]+2*sum[i]*add[i]+t*sqr(add[i]);answer=ans/len-sqr(ave/len);return answer; } signed main() {freopen("1.txt","r",stdin);n=read();q=read();t=(int)sqrt(n)+1;for(register int i=1;i<=n;i++) scanf("%lf",a+i);for(register int i=1;i<=t;i++) {L[i]=R[i-1]+1,R[i]=min(R[i-1]+t,n);for(register int j=L[i];j<=R[i];j++) pos[j]=i,sum[i]+=a[j],sumaf[i]+=sqr(a[j]);}while(q--){opt=read();if(opt==1){l=read();r=read();scanf("%lf",&d);Add(l,r,d);}if(opt==2){l=read();r=read();printf("%.4lf\n",ask(l,r));}if(opt==3){l=read();r=read();printf("%.4lf\n",askfc(l,r));}} }

　　

轉(zhuǎn)載于:https://www.cnblogs.com/ainiyuling/p/11206961.html

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