线段树 ：单点修改，区间查询

题目描述

思路

代码

#include <cstdio>
#include <cstring>
int n, m;
struct {
	int at[1000005];
	long long int arr[1000005 << 2];
	void build(int k, int l, int r) {
		if (l == r) {
			arr[k] = at[l];
			return;
		}
		int mid = l + r >> 1;
		this->build(k << 1, l, mid);
		this->build(k << 1 | 1, mid + 1, r);
		arr[k] = arr[k << 1] + arr[k << 1 | 1];
	}
	void change(int k, int l, int r, int x, int y, int v) {
		if (x > r || y < l) return;
		if (x <= l && r <= y) {
			arr[k] += v;
			return;
		}
		int mid = l + r >> 1;
		this->change(k << 1, l, mid, x, y, v);
		this->change(k << 1 | 1, mid + 1, r, x, y, v);
		arr[k] = arr[k << 1] + arr[k << 1 | 1]; 
	}
	long long query(int k, int l, int r, int x, int y) {
		if (x > r || y < l) return 0;
		if (x <= l && r <= y) return arr[k];
		int mid = l + r >> 1;
		return this->query(k << 1, l, mid, x, y) + this->query(k << 1 | 1, mid + 1, r, x, y);
	}
} t;

inline int read() {
	int s = 0, f = 1;
	char ch = getchar();
	while (ch < '0' || ch > '9') {
		if (ch == '-') f = -1;
		ch = getchar();
	}
	while (ch >= '0' && ch <= '9') s = s * 10 + ch - '0', ch = getchar();
	return s * f;
}
int main() {
	n = read(), m = read();
	for (register int i = 1; i <= n; ++i) t.at[i] = read();
	t.build(1, 1, n);
	for (register int i = 1, a, b, c; i <= m; ++i) {
		a = read(), b = read(), c = read();
		if (a == 1) {
			t.change(1, 1, n, b, b, c);
		} else {
			printf("%lld\n", t.query(1, 1, n, b, c));
		}
	}
	return 0;
}