https://www.luogu.org/problemnew/show/P3374

 1 #include <iostream>
 2 #include <cstdio>
 3 using namespace std;
 4 #define rson (o<<1|1)
 5 #define lson (o<<1)
 6 const int N = 530000<<1;//zkw線段樹只能查詢(0,bit)，所以只有bit-2個葉節點，bit-2<n要再擴大 
 7 int M, n, tree[N], m, q; 
 8 inline int
 
 read(){
 9     register int c = getchar(), x = 0, f = 1; 
10     while(!isdigit(c)) {if (c == ‘-‘) f = -1; c = getchar();}
11     while(isdigit(c)) x = (x<<3)+(x<<1)+(c^48), c = getchar();
12     return x*f;
13 } 
14 inline void pushup(int o){
15     tree[o] = tree[lson] + tree[rson];
 
16 } 
17 inline void build(){
18   for(M = 1; M < n; M <<= 1);
19   for(int i = 1; i <= n; ++i) tree[i+M] = read();
20   for(int i = M-1; i; --i) pushup(i);    
21 }
22 inline void update(int pos, int k){
23   for(tree[pos+=M]+=k, pos>>=1;pos;pos>>=1)
24     pushup(pos);
 
25 }
26 inline int Sum(int l, int r){
27     int ans = 0;
28   // l=l+M-1->將查詢區間改為L-1，r=r+M+1->將查詢區間改為R+1
29   // l^r^1 -> 相當於判斷l與r是否是兄弟節點
30     for(l=l+M-1,r=r+M+1;l^r^1;l>>=1,r>>=1){
31         if (~l&1) //l%2==0 -->l左兒子
32             ans += tree[l^1];
33         if (r&1)//r%2==1
34             ans += tree[r^1]; 
35     }
36     return ans;
37 }
38 int main(void){
39     n = read(), m = read();
40     build();
41     while(m--){
42         int opt = read(), x = read(), y = read();
43         if (opt==1) update(x,y);
44         else printf("%d\n", Sum(x,y));
45     }
46     return 0;
47 }

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 
 4 #define lowbit(a) a&(-a)
 5 
 6 const int N = 500010;
 7 
 8 int a[N], n, m, x, y, k;
 9 
10 inline void update(int x, int k){
11     while(x <= n){
12         a[x] += k;
13         x += lowbit(x);
14     }
15 }
16 
17 inline int Sum(int x){
18     int ans = 0; 
19     while(x > 0){
20         ans += a[x];
21         x -= lowbit(x);
22     }
23     return ans;
24 }
25 
26 int main(void){
27     scanf("%d%d", &n, &m);
28     for(int i = 1; i <= n; ++i){
29         int tmp; scanf("%d", &tmp);update(i,tmp);
30     }
31     while(m--){
32         int bs;
33         scanf("%d%d%d", &bs, &x, &y);
34         if (bs == 1) update(x, y);
35         else printf("%d\n", Sum(y)-Sum(x-1));
36     }
37     
38     return 0;
39 }

[模板]樹狀數組1/ZKW線段樹