题目

代码
cpp
#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int a[N];
int br[N], bl[N], id[N], bcnt, L;
vector<int> bs[1010];
int main()
{
int n;
cin >> n;
for(int i = 1; i <= n; i++)
cin >> a[i];
L = sqrt(n + 1);
for(int i = 1; i <= n; i += L) //只保证了左边界不越界
{
bcnt++;
bl[bcnt] = i;
br[bcnt] = min(i + L - 1, n); //这是分块最容易错误的点,就是没有考虑右边界越界
for(int j = bl[bcnt]; j <= br[bcnt]; j++)
bs[bcnt].push_back(a[j]), id[j] = bcnt; //想直接用下标访问未初始化的向量,需要resize
}
for(int i = 1; i <= bcnt; i++)
sort(bs[i].begin(), bs[i].end());
int m;
cin >> m;
for(int i = 1; i <= m; i++)
{
int op;
cin >> op;
if(op == 1)
{
int x, y;
cin >> x >> y;
int t = a[x];
a[x] = y;
int bid = id[x];
auto it = lower_bound(bs[bid].begin(), bs[bid].end(), t);
*it = y;
sort(bs[bid].begin(), bs[bid].end());
}
else if(op == 2)
{
int l, r, p;
cin >> l >> r >> p;
int cnt = 0;
if(id[l] == id[r])
{
for(int j = l; j <= r; j++)
if(a[j] < a[p]) cnt++;
}
else
{
for(int j = id[l] + 1; j < id[r]; j++)
{
auto it = lower_bound(bs[j].begin(), bs[j].end(), a[p]);
if(it == bs[j].end()) cnt += br[j] - bl[j] + 1;
else cnt += (it - bs[j].begin());
}
for(int j = l; j <= br[id[l]]; j++)
if(a[j] < a[p]) cnt++;
for(int j = bl[id[r]]; j <= r; j++)
if(a[j] < a[p]) cnt++;
}
cout << cnt + 1 << ' ';
}
}
}