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[][],llog2[];//用llog2数组进行优化
 int n,k;

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

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

 int work(){
     int pre_num = -, pre_tot = -, pre_sum;
     for(int i = ; 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 = ;
         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 + , 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+, j);
                 if(tot > k)
                     return i;
             }
             pre_num = num;
             pre_tot = tot;
             pre_sum = sum;
         }
     }
     return -;
 }

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