#include <bits/stdc++.h>
using namespace std;
int n, q, ty[200010];
long long h[200010], v[200010], x[200010], p[200010];
long long cn, ls[200010];
struct TREE {
  long long tr[200010];
  inline void add(int x, long long z) {
    for (; x <= cn; x += (x & -x)) tr[x] += z;
  }
  inline long long sum(int x) {
    long long s = 0;
    for (; x; x -= (x & -x)) s += tr[x];
    return s;
  }
} S1, S2;
double check(double p) {
  int l = 1, r = cn, x = 0;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (ls[mid] <= p)
      x = mid, l = mid + 1;
    else
      r = mid - 1;
  }
  return p * S1.sum(x) - S2.sum(x);
}
int main() {
  scanf("%d%d", &n, &q);
  for (int i = 1; i <= n; i++) scanf("%lld", &h[i]), ls[++cn] = h[i];
  for (int i = 1; i <= q; i++) {
    scanf("%d", &ty[i]);
    if (ty[i] & 1)
      scanf("%lld%lld", &p[i], &x[i]), ls[++cn] = x[i];
    else
      scanf("%lld", &v[i]);
  }
  sort(ls + 1, ls + cn + 1);
  cn = unique(ls + 1, ls + cn + 1) - ls - 1;
  for (int i = 1, wz; i <= n; i++)
    wz = lower_bound(ls + 1, ls + cn + 1, h[i]) - ls, S2.add(wz, h[i]),
    S1.add(wz, 1);
  for (int i = 1, wz; i <= q; i++) {
    if (ty[i] & 1) {
      wz = lower_bound(ls + 1, ls + cn + 1, h[p[i]]) - ls;
      S1.add(wz, -1);
      S2.add(wz, -h[p[i]]);
      h[p[i]] = x[i];
      wz = lower_bound(ls + 1, ls + cn + 1, h[p[i]]) - ls;
      S1.add(wz, 1);
      S2.add(wz, h[p[i]]);
    } else {
      double l = 0, r = 1e18;
      while (r - l > 1e-5) {
        double mid = (l + r) / 2;
        if (check(mid) >= v[i])
          r = mid;
        else
          l = mid;
      }
      printf("%.5lf\n", r);
    }
  }
  return 0;
}
