我的分块 代码，在 query 中没有特判 $L=R$ 的情况，却拿到了满分。

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 5e5 + 5;
const int M = 7e2 + 10;
int a[N], id[N], l[M], r[M], sum[M];
int n, m;
void add(int x, int k){
	a[x] += k;
	sum[id[x]] += k;
}
int query(int x, int y){
	int L = id[x], R = id[y], res = 0;
	for (int i = x; i <= r[L]; i ++){
		res += a[i];
	}
	for (int i = l[R]; i <= y; i ++){
		res += a[i];
	}
	for (int i = L + 1; i < R; i ++){
		res += sum[i];
	}
	return res;
}
signed main(){
	cin >> n >> m;
	for (int i = 1; i <= n; i ++){
		cin >> a[i];
	}
	int t = sqrt(n), tot = 0;
	for (int i = 1; i * t <= n; i ++){
		l[i] = (i - 1) * t + 1;
		r[i] = i * t;
		for (int j = l[i]; j <= r[i]; j ++){
			sum[i] += a[j];
			id[j] = i;
		}
		tot = i;
	}
	if (r[tot] < n){
		tot ++;
		l[tot] = (tot - 1) * t + 1;
		r[tot] = n;
		for (int j = l[tot]; j <= r[tot]; j ++){
			sum[tot] += a[j];
			id[j] = tot;
		}
	}
// 	for (int i = 1; i <= tot; i ++){
// 		cout << l[i] << " " << r[i] << " " << sum[i] << "\n";
// 	}
	while (m --){
		int op, x, y;
		cin >> op >> x >> y;
		if (op == 1){
			add(x, y);
		}
		else{
			cout << query(x, y) << "\n";
		}
	}
	return 0;
}

hack:

5 1
1 1 1 1 1
2 1 2

正确输出应该是 $2$，我的代码输出了 $4$。