解题思路：线段树模板题，好久没写线段树了，练练手，发现不像以前那么迷茫了，
脑海中已经可以有清晰的图像了。这样，比较科学。上代码：
1 #include<cstdio> 2 #include<cstring> 3 #include<algorithm> 4 using namespace std; 5 #define lson l,m,rt<<1 6 #define rson m+1,r,rt<<1 | 1 7 const int maxn = 50005; 8 int A[maxn<<2], t, n, kase = 1; 9 char str[10]; 10 11 void Sum(int rt) 12 { 13 A[rt] = A[rt<<1] + A[rt<<1 | 1]; 14 } 15 16 void Build(int l, int r, int rt) 17 { 18 if(l == r) 19 { 20 scanf("%d", &A[rt]); 21 return ; 22 } 23 int m = (l + r) >> 1; 24 Build(lson); 25 Build(rson); 26 Sum(rt); 27 } 28 29 void Update(int p, int add, int l, int r, int rt) 30 { 31 if(l == r) 32 { 33 A[rt] += add; 34 return ; 35 } 36 int m = (l + r) >> 1; 37 if(p <= m) Update(p, add, lson); 38 else Update(p, add, rson); 39 Sum(rt); 40 } 41 42 int Query(int ll, int rr, int l, int r, int rt) 43 { 44 if(ll <= l && rr >= r) return A[rt]; 45 int m = (l + r) >> 1; 46 int ret = 0; 47 if(ll <= m) ret += Query(ll, rr, lson); 48 if(rr > m) ret += Query(ll, rr, rson); 49 return ret; 50 } 51 52 53 54 int main() 55 { 56 int a, b; 57 scanf("%d", &t); 58 while(t--) 59 { 60 scanf("%d", &n); 61 Build(1, n, 1); 62 printf("Case %d: ",kase++); 63 while(1) 64 { 65 scanf("%s", str); 66 if(str[0] == 'E') break; 67 if(str[0] == 'Q') 68 { 69 scanf("%d %d", &a, &b); 70 int ans = Query(a, b, 1, n, 1); 71 printf("%d ", ans); 72 } 73 if(str[0] == 'A') 74 { 75 scanf("%d %d", &a, &b); 76 Update(a, b, 1, n, 1); 77 } 78 if(str[0] == 'S') 79 { 80 scanf("%d %d", &a, &b); 81 Update(a, -b, 1, n, 1); 82 } 83 } 84 } 85 return 0; 86 }