线段树---分析 && 模板总结

 1 #include <cstdio>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 #define lson l , m , rt << 1
 6 #define rson m + 1 , r , rt << 1 | 1
 7 #define root 1 , n , 1
 8 #define LL long long
 9 #define maxn 50000*5
10 
11 LL ad[maxn<<2];
12 LL su[maxn<<2];
13 void PushUp(int rt) {
14     su[rt] = su[rt<<1] + su[rt<<1|1];
15 }
16 void PushDown(int rt,int m) {
17     if (ad[rt]) {
18         ad[rt<<1] += ad[rt];
19         ad[rt<<1|1] += ad[rt];
20         su[rt<<1] += ad[rt] * (m - (m >> 1));
21         su[rt<<1|1] += ad[rt] * (m >> 1);
22         ad[rt] = 0;
23     }
24 }
25 void build(int l,int r,int rt) {
26     ad[rt] = 0;
27     if (l == r) {
28         scanf("%lld",&su[rt]);
29         return ;
30     }
31     int m = (l + r) >> 1;
32     build(lson);
33     build(rson);
34     PushUp(rt);
35 }
36 void update(int L,int R,int c,int l,int r,int rt) {
37     if (L <= l && r <= R) {
38         ad[rt] += c;
39         su[rt] += (LL)c * (r - l + 1);
40         return ;
41     }
42     PushDown(rt , r - l + 1);
43     int m = (l + r) >> 1;
44     if (L <= m) update(L , R , c , lson);
45     if (m < R) update(L , R , c , rson);
46     PushUp(rt);
47 }
48 LL query(int L,int R,int l,int r,int rt) {
49     if (L <= l && r <= R) {
50         return su[rt];
51     }
52     PushDown(rt , r - l + 1);
53     int m = (l + r) >> 1;
54     LL ret = 0;
55     if (L <= m) ret += query(L , R , lson);
56     if (m < R) ret += query(L , R , rson);
57     return ret;
58 }
59 int main() {
60     int n,number=1;
61     int T;
62     scanf("%d",&T);
63     while(T--){
64         printf("Case %d:\n",number++);
65         scanf("%d",&n);
66         build(root);
67         char op[20];
68         int a , b ;
69         while (scanf("%s",op) && op[0]!=‘E‘) {
70             if (op[0] == ‘Q‘) {
71                 scanf("%d%d",&a,&b);
72                 printf("%lld\n",query(a , b ,root));
73             } else {
74                 scanf("%d%d",&a,&b);
75                 if(op[0]==‘A‘)
76                     update(a , a , b , root);
77                 else
78                     update(a , a , -b , root);
79 
80             }
81         }
82     }
83     return 0;
84 }