原题：

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题解：

#include
     
      #include
      
       #include
       
        #define N 50005typedef long long ll;using namespace std;ll n,c[N],a[N],b[N],sum[N],f[N],L,q[N],l,r;ll sq(ll x){
    return x*x;}double getD(ll j,ll k){    return 1.0*(f[j]+sq(b[j])-f[k]-sq(b[k]))/(2*(b[j]-b[k]));}int main(){    scanf("%lld%lld",&n,&L);    for (ll i=1;i<=n;i++)        {        scanf("%lld",&c[i]);        sum[i]=sum[i-1]+c[i];        a[i]=sum[i]+i-1-L;        b[i]=sum[i]+i;    }    for (ll i=1;i<=n;i++)    {        while (l