线段树的基本知识可以先google一下，不是很难理解

线段树功能:update:单点增减 query:区间求和

#include 
     
      #define lson l, m, rt<<1#define rson m+1, r, rt<<1|1using namespace std;const int MAXN = 50008;int sum[MAXN<<2];void build(int l, int r, int rt){    if(l == r)    {        scanf("%d", &sum[rt]);        return;    }    int m = (l + r) >> 1;    build(lson);    build(rson);    sum[rt] = sum[rt<<1] + sum[rt<<1|1];}int query(int L, int R, int l, int r, int rt){    if(L <= l && r <= R) return sum[rt];    int ret = 0;    int m = (l + r) >> 1;    if(L <= m) ret += query(L, R, lson);    if(R > m) ret += query(L, R, rson);    return ret;}void updata(int p, int add, int l, int r, int rt){    if(l == r)    {        sum[rt] += add;        return;    }    int m = (l + r) >> 1;    if(p <= m) updata(p, add, lson);    else updata(p, add, rson);    sum[rt] = sum[rt<<1] + sum[rt<<1|1];}int main(){//    freopen("in.txt", "r", stdin);    int T, Case = 0;    scanf("%d", &T);    while(T--)    {        int n;        scanf("%d", &n);        build(1, n, 1);        printf("Case %d:\n", ++Case);        char s[10];        while(~scanf("%s", s))        {            if(s[0] == 'E') break;            int a,b;            scanf("%d%d", &a, &b);            if(s[0] == 'Q') printf("%d\n", query(a, b, 1, n, 1));            else if(s[0] == 'A') updata(a, b, 1, n, 1);            else updata(a, -b, 1, n, 1);        }    }    return 0;}