[poj3368]Frequent values(rmq)

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 #include<cstdlib>
 5 #include<cmath>
 6 #include<iostream>
 7 using namespace std;
 8 typedef long long ll;
 9 int a[100002],b[100002];
10 int min1[100002][22],max1[100002][22],n,q;
11 void rmq(int n){
12     int lg=int(log10(n)/log10(2));
13     for(int i=1;i<=n;i++) min1[i][0]=max1[i][0]=b[i];
14     for(int j=1;j<=lg;j++){
15         for(int i=1;i+(1<<j)-1<=n;i++){
16             max1[i][j]=max(max1[i][j-1],max1[i+(1<<(j-1))][j-1]);
17             //min1[i][j]=min(min1[i][j-1],min1[i+(1<<(j-1))][j-1]);
18         }
19     }
20 }
21 
22 int query(int l,int r){
23     if(l>r) return 0;
24     int k=(int)(log(r-l+1)/log(2.0));
25     return max(max1[l][k],max1[r-(1<<k)+1][k]);
26 }
27 int main(){
28     int n,q;
29     while(scanf("%d",&n)!=EOF&&n){
30         scanf("%d",&q);
31         for(int i=1;i<=n;i++) scanf("%d",a+i);
32         for(int i=1;i<=n;i++){
33             if(a[i]==a[i-1]) b[i]=b[i-1]+1;
34             else b[i]=1;
35         }
36         rmq(n);
37         while(q--){
38             int t1,t2,t=0;
39             scanf("%d%d",&t1,&t2);
40             t=t1;
41                while(t<=t2&&a[t]==a[t-1]) t++;
42                 int maxres=query(t,t2);
43                 maxres=max(maxres,t-t1);
44                 printf("%d\n",maxres);
45             }
46     }
47     return 0;
48 }