HDU3486 RMQ

/*多么变态的一道题，交了18次*/


#include<cstdio>
#include<cstring>
#include<cmath>
#define max(a,b) (a>b?a:b)
int dp[200005][20],llog2[200005];//用llog2数组进行优化
int n,k;

void DpMax(){
    for(int j=1;j<=llog2[n]+1;j++){//llog2
        for(int i=1;i+(1<<j)-1<=n;i++){
            dp[i][j]=max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
        }
    }
}

int GetMax(int L,int R){
    int j=llog2[R-L+1];//llog2
    return max(dp[L][j],dp[R-(1<<j)+1][j]);
}

int work(){
    int pre_num = -1, pre_tot = -1, pre_sum;
    for(int i = 1; i <= n; ++i) //分成i组
    {
        int num = n / i;    //每组num个
        int sum = num * i;  //总的多少人
        int tot = 0;
        if(num == pre_num)  //如果和前一次一样则从前一次继续累加即可
        {
            tot = pre_tot;
            for(int j = pre_sum + num; j <= sum; j+= num)
            {
                tot += GetMax(j - num + 1, j);
                if(tot > k)
                    return i;
            }
            pre_tot = tot;
            pre_sum = sum;
        }
        else
        {
            for(int j = num; j <= sum; j += num)
            {
                tot += GetMax(j-num+1, j);
                if(tot > k)
                    return i;
            }
            pre_num = num;
            pre_tot = tot;
            pre_sum = sum;
        }
    }
    return -1;
}

int main(){
    for(int i=2;i<200005;++i){//llog2
        llog2[i]=(i&(i-1))==0?llog2[i-1]+1:llog2[i-1];
    }
    while(scanf("%d%d",&n,&k),n>0||k>0){
        memset(dp,0,sizeof(dp));
        for(int i=1;i<=n;i++){
            scanf("%d",&dp[i][0]);
        }
        DpMax();
        printf("%d
",work());
    }
}