题目链接：http://poj.org/problem?id=3468
线段树区间更新查询的样题，注意数据范围。连要更新的数据也必须是long long。
1 #include <algorithm>
2 #include <iostream>
3 #include <iomanip>
4 #include <cstring>
5 #include <climits>
6 #include <complex>
7 #include <cassert>
8 #include <cstdio>
9 #include <bitset>
10 #include <vector>
11 #include <deque>
12 #include <queue>
13 #include <stack>
14 #include <ctime>
15 #include <set>
16 #include <map>
17 #include <cmath>
18 using namespace std;
19
20 typedef long long LL;
21 #define lrt rt << 1
22 #define rrt rt << 1 | 1
23 const int maxn = 100100;
24 LL sum[maxn<<2], add[maxn<<2];
25 int n, q;
26 char cmd[2];
27
28 void pushUP(int rt) {
29 sum[rt] = sum[lrt] + sum[rrt];
30 }
31
32 void pushDOWN(int rt, int len) {
33 if(add[rt]) {
34 sum[lrt] += (len - len / 2) * add[rt];
35 sum[rrt] += len / 2 * add[rt];
36 add[lrt] += add[rt];
37 add[rrt] += add[rt];
38 add[rt] = 0;
39 }
40 }
41
42 void build(int l, int r, int rt) {
43 add[rt] = 0;
44 if(l == r) {
45 scanf("%I64d", &sum[rt]);
46 return;
47 }
48 int mid = (l + r) >> 1;
49 build(l, mid, lrt);
50 build(mid+1, r, rrt);
51 pushUP(rt);
52 }
53
54 void update(int L, int R, LL c, int l, int r, int rt) {
55 if(L <= l && r <= R) {
56 add[rt] += c;
57 sum[rt] += (LL)c * (r - l + 1);
58 return;
59 }
60 pushDOWN(rt, r-l+1);
61 int mid = (l + r) >> 1;
62 if(L <= mid) update(L, R, c, l, mid, lrt);
63 if(mid < R) update(L, R, c, mid+1, r, rrt);
64 pushUP(rt);
65 }
66
67 LL query(int L, int R, int l, int r, int rt) {
68 if(L <= l && r <= R) return sum[rt];
69 pushDOWN(rt, r-l+1);
70 int mid = (l + r) >> 1;
71 LL ret = 0;
72 if(L <= mid) ret += query(L, R, l, mid, lrt);
73 if(mid < R) ret += query(L, R, mid+1, r, rrt);
74 return ret;
75 }
76
77 int main() {
78 // freopen("in", "r", stdin);
79 int l, r, c;
80 while(~scanf("%d%d",&n,&q)) {
81 build(1, n, 1);
82 while(q--) {
83 scanf("%s", cmd);
84 if(cmd[0] == 'Q') {
85 scanf("%d%d",&l,&r);
86 printf("%I64d\n", query(l,r,1,n,1));
87 }
88 else {
89 scanf("%d%d%d",&l,&r,&c);
90 update(l,r,LL(c),1,n,1);
91 }
92 }
93 }
94 return 0;
95 }
来源：https://www.cnblogs.com/kirai/p/4771834.html