P2596

树状数组是个好东西

# include <bits/stdc++.h>
# define Fill(a, b) memset(a, b, sizeof(a))
using namespace std;
const int _(3e5 + 10), INF(2e9), PF(1e5);
inline long long Read(){
    char c = '%'; long long x = 0, z = 1;
    for(; c > '9' || c < '0'; c = getchar()) if(c == '-') z = -1;
    for(; c >= '0' && c <= '9'; c = getchar()) x = x * 10 + c - '0';
    return x * z;
}
int n, m, t[_], id[_], a[_];
char opt[10];
inline void Add(register int x, register int v){  for(; x <= PF * 3; x += x & -x) t[x] += v;  }
inline int Query(register int x){  register int cnt = 0; for(; x; x -= x & -x) cnt += t[x]; return cnt;  }
inline int Find(register int x){
    register int l = 1, r = PF * 3;
    while(l < r){
        register int mid = (l + r) >> 1;
        if(Query(mid) >= x) r = mid;
        else l = mid + 1;
    }
    return l;
}
int main(register int argc, register char *argv[]){
    n = Read(); m = Read();
    for(register int i = 1; i <= n; ++i) a[PF + i] = Read(), Add(PF + i, 1), id[a[PF + i]] = PF + i;
    while(m--){
        scanf(" %s", opt); register int x = Read(), y, p, q;
        if(opt[0] == 'T'){
            p = Find(1);
            a[id[x]] = 0; Add(id[x], -1);
            id[x] = p - 1;
            a[id[x]] = x; Add(id[x], 1);
        }
        else if(opt[0] == 'B'){
            p = Find(n);
            a[id[x]] = 0; Add(id[x], -1);
            id[x] = p + 1;
            a[id[x]] = x; Add(id[x], 1);
        }
        else if(opt[0] == 'I'){
            y = Read(); q = Query(id[x]);
            p = Find(q + y); register int t = a[p];
            swap(a[p], a[id[x]]); swap(id[x], id[t]);
        }
        else if(opt[0] == 'A') printf("%d\n", Query(id[x]) - 1);
        else printf("%d\n", a[Find(x)]);
    }
    return 0;
}