H - Frequent values
Problem F: Frequent values
You are given a sequence of n integers a1 , a2 , ... , an in non-decreasing order. In addition to that, you are given several queries consisting of indices i and j (1 ≤ i ≤ j ≤ n). For each query, determine the most frequent value among the integers ai , ... , aj.
Input Specification
The input consists of several test cases. Each test case starts with a line containing two integers n and q (1 ≤ n, q ≤ 100000). The next line contains n integers a1 , ... , an (-100000 ≤ ai ≤ 100000, for each i ∈ {1, ..., n}) separated by spaces. You can assume that for each i ∈ {1, ..., n-1}: ai ≤ ai+1. The following q 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 Specification
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 10
2 3
1 10
5 10
0
Sample Output
1
4
3
RMQ问题
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cmath> 5 #include <algorithm> 6 #include <string> 7 #include <vector> 8 #include <stack> 9 #include <queue> 10 #include <set> 11 #include <map> 12 #include <list> 13 #include <iomanip> 14 #include <cstdlib> 15 #include <sstream> 16 using namespace std; 17 typedef long long LL; 18 const int INF=0x5fffffff; 19 const double EXP=1e-6; 20 const int MS=100005; 21 22 int dp[MS][20]; 23 int a[MS],cnt[MS]; 24 int num[MS],l[MS],r[MS]; 25 int n,q; 26 27 void RMQ_init() 28 { 29 for(int i=0;i<n;i++) 30 dp[i][0]=cnt[i]; 31 for(int j=1;(1<<j)<=n;j++) 32 { 33 for(int i=0;i+(1<<j)-1<n;i++) 34 dp[i][j]=max(dp[i][j-1],dp[i+(1<<(j-1))][j-1]); 35 } 36 } 37 38 int RMQ(int l,int r) 39 { 40 int k=0; 41 while(1<<(k+1)<=r-l+1) 42 k++; 43 return max(dp[l][k],dp[r-(1<<k)+1][k]); 44 } 45 46 47 48 int main() 49 { 50 while(scanf("%d%d",&n,&q)==2&&n) 51 { 52 for(int i=0;i<n;i++) 53 scanf("%d",&a[i]); 54 a[n]=a[n-1]+1; 55 int start=0; 56 int id=0; 57 for(int i=0;i<=n;i++) 58 { 59 if(i>0&&a[i]>a[i-1]) 60 { 61 for(int j=start;j<i;j++) 62 r[j]=i-1; 63 cnt[id]=i-start; 64 id++; 65 start=i; 66 } 67 l[i]=start; 68 num[i]=id; 69 } 70 n=id; 71 RMQ_init(); 72 int x,y; 73 while(q--) 74 { 75 scanf("%d%d",&x,&y); 76 x--; 77 y--; 78 int ans=0; 79 if(num[x]==num[y]) 80 { 81 printf("%d\n",y-x+1); 82 continue; 83 } 84 ans=max(r[x]-x+1,y-l[y]+1); 85 if(num[x]+1<num[y]) 86 ans=max(ans,RMQ(num[x]+1,num[y]-1)); 87 printf("%d\n",ans); 88 } 89 90 } 91 return 0; 92 }
