UVA-11235 frequent values (RMQ)

The main idea: in a non-descending sequence of length n, there are M queries, each query (I,J) indicates the number of occurrences of the most frequently occurring element in the interval (i,j).

Title analysis: Because the sequence is ordered, you can segment the sequence and record the number of elements per paragraph, the segment num (i) each element belongs to, the left endpoint L (i) and the right endpoint R (i) for each element. So for each query:

Ans (i,j) =max (max (R (i)-i+1,j-l (j) +1), RMQ (num (i) +1,num (j)-1)).

Ans (i,j) =r-j+1 (if I and J belong to the same paragraph)

The code is as follows:

# include<iostream># include<cstdio># include<cstring># include<vector># include<queue ># include<list># include<set># include<map># include<string># include<cmath># include<cstdlib># include<algorithm>using namespace std;# define LL long longconst int n=1005;const int INF=1 000000000;const LL oo=0x7fffffffffffffff;const Double eps=1e-10;int n,m;int a[n*100];vector<int>v;int num[N*100 ];int l[n*100];int r[n*100];int d[n*100][20];void rmq_init () {int len=v.size (); for (int i=0;i<len;++i) d[i][0]=v[i]; for (int j=1, (1<<j) <=len;++j) for (int i=0;i+ (1&LT;&LT;J) -1<len;++i) D[i][j]=max (d[i][j-1],d[i+ (1< < (J-1))][j-1]);} void Init () {v.clear (); int cnt=1;num[0]=0; l[0]=0;for (int i=1;i<n;++i) {if (a[i]==a[i-1]) {++cnt;num[i]=num[i-1]; L[I]=L[I-1];} Else{v.push_back (CNT); num[i]=v.size (); L[i]=i;cnt=1;}} V.push_back (CNT); r[n-1]=n-1;for (int i=n-2;i>=0;--i) {if (a[i]==a[i+1]) r[i]=r[i+1];elser[i]=i;} Rmq_init ();} int QuerY (int l,int R) {if (l>r) return 0;int k=0;while ((1<< (k+1)) <=r-l+1) ++k;return Max (d[l][k],d[r-(1<<k) + 1][k]);} int solve (int l,int r) {if (Num[l]==num[r]) return R-l+1;else{return Max (max (r[l]-l+1,r-l[r]+1), query (num[l]+1,num[r]- 1));}} int main () {while (scanf ("%d", &n) &&n) {scanf ("%d", &m), for (int i=0;i<n;++i) scanf ("%d", a+i); Init () int L,r;while (m--) {scanf ("%d%d", &l,&r),--l,--r;printf ("%d\n", Solve (L,r));}} return 0;}

　　

UVA-11235 frequent values (RMQ)