HDU3486 RMQ

 1 /*多么变态的一道题，交了18次*/

 2 

 3 

 4 #include<cstdio>

 5 #include<cstring>

 6 #include<cmath>

 7 #define max(a,b) (a>b?a:b)

 8 int dp[200005][20],llog2[200005];//用llog2数组进行优化

 9 int n,k;

10 

11 void DpMax(){

12     for(int j=1;j<=llog2[n]+1;j++){//llog2

13         for(int i=1;i+(1<<j)-1<=n;i++){

14             dp[i][j]=max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);

15         }

16     }

17 }

18 

19 int GetMax(int L,int R){

20     int j=llog2[R-L+1];//llog2

21     return max(dp[L][j],dp[R-(1<<j)+1][j]);

22 }

23 

24 int work(){

25     int pre_num = -1, pre_tot = -1, pre_sum;

26     for(int i = 1; i <= n; ++i) //分成i组

27     {

28         int num = n / i;    //每组num个

29         int sum = num * i;  //总的多少人

30         int tot = 0;

31         if(num == pre_num)  //如果和前一次一样则从前一次继续累加即可

32         {

33             tot = pre_tot;

34             for(int j = pre_sum + num; j <= sum; j+= num)

35             {

36                 tot += GetMax(j - num + 1, j);

37                 if(tot > k)

38                     return i;

39             }

40             pre_tot = tot;

41             pre_sum = sum;

42         }

43         else

44         {

45             for(int j = num; j <= sum; j += num)

46             {

47                 tot += GetMax(j-num+1, j);

48                 if(tot > k)

49                     return i;

50             }

51             pre_num = num;

52             pre_tot = tot;

53             pre_sum = sum;

54         }

55     }

56     return -1;

57 }

58 

59 int main(){

60     for(int i=2;i<200005;++i){//llog2

61         llog2[i]=(i&(i-1))==0?llog2[i-1]+1:llog2[i-1];

62     }

63     while(scanf("%d%d",&n,&k),n>0||k>0){

64         memset(dp,0,sizeof(dp));

65         for(int i=1;i<=n;i++){

66             scanf("%d",&dp[i][0]);

67         }

68         DpMax();

69         printf("%d\n",work());

70     }

71 }

72 

73 

74