luogu4168 [Violet]蒲公英

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <vector>
#include <cmath>
#include <map>
using namespace std;
int n, m, bel[40005], a[40005], blc, f[1005][1005], cnt[40005], idx, ans;
int val[40005], uu, vv;
map<int,int> mp;
vector<int> vec[40005];
int mycnt(int uu, int vv, int ww){
    return upper_bound(vec[ww].begin(), vec[ww].end(), vv)-lower_bound(vec[ww].begin(), vec[ww].end(), uu);
}
int query(int uu, int vv){
    int tmpmax=f[bel[uu]+1][bel[vv]-1], tmpcnt=mycnt(uu, vv, tmpmax);
    if(bel[uu]==bel[vv]){
        for(int i=uu; i<=vv; i++){
            int t=mycnt(uu, vv, a[i]);
            if(t>tmpcnt || (t==tmpcnt && a[i]<tmpmax)){
                tmpmax = a[i];
                tmpcnt = t;
            }
        }
    }
    else{
        for(int i=uu; i<=bel[uu]*blc; i++){
            int t=mycnt(uu, vv, a[i]);
            if(t>tmpcnt || (t==tmpcnt && a[i]<tmpmax)){
                tmpmax = a[i];
                tmpcnt = t;
            }
        }
        for(int i=(bel[vv]-1)*blc+1; i<=vv; i++){
            int t=mycnt(uu, vv, a[i]);
            if(t>tmpcnt || (t==tmpcnt && a[i]<tmpmax)){
                tmpmax = a[i];
                tmpcnt = t;
            }
        }
    }
    return tmpmax;
}
int main(){
    cin>>n>>m;
    blc = sqrt(n*log(2)/log(n));
    for(int i=1; i<=n; i++){
        scanf("%d", &a[i]);
        val[++idx] = a[i];
        bel[i] = (i - 1) / blc + 1;
    }
    sort(val+1, val+1+n);
    idx = unique(val+1, val+1+idx) - val - 1;
    for(int i=1; i<=n; i++){
        a[i] = lower_bound(val+1, val+1+idx, a[i]) - val;
        vec[a[i]].push_back(i);
    }
    for(int i=1; i<=n; i=bel[i]*blc+1){
        memset(cnt, 0, sizeof(cnt));
        int tmpmax=0, tmpcnt=0;
        for(int j=i; j<=n; j++){
            cnt[a[j]]++;
            if(cnt[a[j]]>tmpcnt || (cnt[a[j]]==tmpcnt && a[j]<tmpmax)){
                tmpmax = a[j];
                tmpcnt = cnt[a[j]];
            }
            f[bel[i]][bel[j]] = tmpmax;
        }
    }
    while(m--){
        scanf("%d %d", &uu, &vv);
        uu = (uu + ans - 1) % n + 1;
        vv = (vv + ans - 1) % n + 1;
        if(uu>vv)	swap(uu, vv);
        ans = val[query(uu, vv)];
        printf("%d\n", ans);
    }
    return 0;
}