uva 11235 Frequent values

Description

You are given a sequence of n integers a₁ , a₂ , ... , a_n in non-decreasing order. In addition to that, you are given several queries consisting of indicesi and j (1 ≤ i ≤ j ≤ n). For each query, determine the most frequent value among the integersa_i , ... , a_j.

Input

The input consists of several test cases. Each test case starts with a line containing two integersn and q (1 ≤ n, q ≤ 100000). The next line containsn integers a₁ , ... , a_n (-100000 ≤ a_i ≤ 100000, for eachi ∈ {1, ..., n}) separated by spaces. You can assume that for each i ∈ {1, ..., n-1}: a_i ≤ a_i+1. The followingq lines contain one query each, consisting of two integers i and j (1 ≤ i ≤ j ≤ n), which indicate the boundary indices for the
query.

The last test case is followed by a line containing a single 0.

Output

For each query, print one line with one integer: The number of occurrences of the most frequent value within the given range.

Sample Input

10 3-1 -1 1 1 1 1 3 10 10 102 31 105 100

Sample Output

143

Source

Ulm Local 2007

解析
RMQ。cnt[i]表示在位置i处，前面有多少与这个数相同的数。对于询问a,b找cnt[a]到cnt[b]之间的最大值即可。
询问时有这样一个处理

for(int i=1;i<=Q;i++){int a,b; scanf("%d%d",&a,&b);int t=a;while(t<=b && cnt[t]==cnt[t-1]) t++;printf("%d\n",max(RMQ(t,b),t-a));}

记得初始化cnt[0]=-INF

#include<cstdio>#include<algorithm>using namespace std;#define LOCALint f[200100][31],cnt[200100],N,Q;void readdata(){scanf("%d",&Q);cnt[0]=-0x3f3f3f3f;scanf("%d",&cnt[1]); f[1][0]=1;for(int i=2;i<=N;i++){scanf("%d",&cnt[i]);if(cnt[i]>cnt[i-1]) f[i][0]=1;else f[i][0]=f[i-1][0]+1;}}void RMQ_ST(){for(int i=1;(1<<i)<N;i++)for(int j=1;(j+(1<<i)-1)<=N;j++)f[j][i]=max(f[j][i-1],f[j+(1<<(i-1))][i-1]);}int RMQ(int a,int b){if(a==b) return 1;int t=0;while(b-a+1>(1<<t)) t++; t--;return max(f[a][t],f[b-(1<<t)+1][t]);}void Ask(){for(int i=1;i<=Q;i++){int a,b; scanf("%d%d",&a,&b);int t=a;while(t<=b && cnt[t]==cnt[t-1]) t++;printf("%d\n",max(RMQ(t,b),t-a));}}int main(){while(scanf("%d",&N)){if(N==0) break;readdata();RMQ_ST();Ask();}#ifdef LOCALwhile(1);#endifreturn 0;}