为什么就是过不去......

#include <algorithm>
#include <cmath>
#include <cstring>
#include <iostream>
using namespace std;
int n, m;
int presum[205][40005], bes[205][205]; //前缀和    众数
int arr[100005];                       //读入的数组
int mp[100005];                        //离散化
int cnt[40005];
int bsiz, lst;
int belong(int x) { return x / bsiz; }//从0开始编号方便分块
int st(int x) { return x * bsiz; }//照着有图那篇题解的思想做的......
int ed(int x) { return st(x + 1) - 1; }
int lastans;
inline char gc()
{
    static char bb[1000000], *s = bb, *t = bb;
    return s == t && (t = (s = bb) + fread(bb, 1, 1000000, stdin), s == t) ? EOF : *s++;
}
inline int read()
{
    int x = 0;
    char ch = gc();
    while (ch < 48)
        ch = gc();
    while (ch >= 48)
        x = x * 10 + ch - 48, ch = gc();
    return x;
}
int main()
{
    n = read(), m = read();
    bsiz = ceil(sqrt(n));
    lst = belong(n - 1);
    for (int i = 0; i < n; i++)
        mp[i] = arr[i] = read();
    sort(mp, mp + n);
    int dsiz = unique(mp, mp + n) - mp;
    for (int i = 0; i < n; i++)
        arr[i] = lower_bound(mp, mp + dsiz, arr[i]) - mp;
    for (int i = 0; i < n; i++)
    {
        if (i && (!(i % bsiz)))
            for (int u = 0; u < dsiz; u++)
                presum[i / bsiz - 1][u] = presum[lst][u];
        presum[lst][arr[i]]++;
    }
    for (int i = 0; i <= lst; i++)
        for (int u = i; u <= lst; u++)
        {
            memset(cnt, 0, sizeof(cnt));
            int maxp = 0;
            for (int j = st(i); j <= min(ed(u), n - 1); j++)
            {
                cnt[arr[j]]++;
                if (cnt[maxp] == cnt[arr[j]])
                    maxp = min(maxp, arr[j]);
                if (cnt[maxp] < cnt[arr[j]])
                    maxp = arr[j];
            }
            bes[i][u] = maxp;
        }
    for (int i = 0; i < m; i++)
    {
        int l = (read() + lastans - 1) % n, r = (read() + lastans - 1) % n; //l--,r--;
        if (l > r)
            swap(l, r);
        if (belong(r) - belong(l) < 2)
        {
            int maxp = 0;
            memset(cnt, 0, sizeof(cnt));
            for (int u = l; u <= r; u++)
            {
                cnt[arr[u]]++;
                if (cnt[arr[u]] == cnt[maxp])
                    maxp = min(maxp, arr[u]);
                else if (cnt[arr[u]] > cnt[maxp])
                    maxp = arr[u];
            }
            lastans = mp[maxp];
            cout << mp[maxp] << endl;
        }
        else
        {
            memset(cnt, 0, sizeof(cnt));
            int bell = belong(l), belr = belong(r);
            cnt[bes[bell + 1][belr - 1]] = presum[belr - 1][bes[bell + 1][belr - 1]] - presum[bell][bes[bell + 1][belr - 1]];
            int maxp = 0;
            for (int u = l; u <= ed(bell); u++)
            {
                if (!cnt[arr[u]])
                    cnt[arr[u]] = presum[belr - 1][arr[u]] - presum[bell][arr[u]];
                cnt[arr[u]]++;
                if (cnt[arr[u]] == cnt[maxp])
                    maxp = min(maxp, arr[u]);
                else if (cnt[arr[u]] > cnt[maxp])
                    maxp = arr[u];
            }
            for (int u = st(belr); u <= r; u++)
            {
                if (!cnt[arr[u]])
                    cnt[arr[u]] = presum[belr - 1][arr[u]] - presum[bell][arr[u]];
                cnt[arr[u]]++;
                if (cnt[arr[u]] == cnt[maxp])
                    maxp = min(maxp, arr[u]);
                else if (cnt[arr[u]] > cnt[maxp])
                    maxp = arr[u];
            }
            lastans = mp[maxp];
            cout << mp[maxp] << endl;
        }
    }
}

自己的样例和其他人的样例都能过,求差错......