Codeforces 460C

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
typedef long long ll;
int a[100005],b[100005],sum[100005];
int n,m,k;
bool judge(int mid)
{
    int step=m,add=0;
    memset(sum,0,sizeof(sum));
    for(int i=0;i<n;i++)
    b[i]=a[i];
    for(int i=0;i<n;i++)
    {
        add+=sum[i];
        b[i]+=add;
        if(b[i]<mid)
        {
            int temp=mid-b[i];
            b[i]=mid;
            step-=temp;
            add+=temp;
            sum[min(i+k,n)]-=temp;
            if(step<0)
            return false;
        }
    }
    return true;
}
int main()
{
    while(cin>>n>>m>>k)
    {
        int minn=1e9;
        int maxx=0;
        for(int i=0;i<n;i++)
        {
            cin>>a[i];
            minn=min(minn,a[i]);
            maxx=max(maxx,a[i]);
        }
        int low=minn,high=m+maxx;
        int ans=minn;
        while(low<=high)
        {
            int mid=(low+high)>>1;
            if(judge(mid))
            {
                ans=max(ans,mid);
                low=mid+1;
            }
            else
            high=mid-1;
        }
        cout<<ans<<endl;
    }
}