題目點著

題意：單點修改，區間查詢，樹狀陣列
注意輸出格式，每組資料之間有回車，最後一組沒有

#include<cstdio>
#include<cstring>
#include<iostream>
typedef long long LL;
using namespace std;
const int N=233333;
int n,a[N],T[N];
char st[5];

void add(int k,int num){
    while (k<=n){
        T[k]+=num;
        k+=k&(-k);
    }
}
LL sum(int
 
 k){
    LL s=0;
    while (k){
        s+=T[k];
        k-=k&(-k);
    }
    return s;
}

int main(){
    //freopen("fuck.in","r",stdin);
    for (int cas=1;scanf("%d",&n)==1&&n;cas++){
        memset(T,0,sizeof(T));
        for (int i=1;i<=n;i++){
            scanf("%d\n",&a[i]);
            add(i,a[i]);
        }
        if
 
 (cas>1)puts("");
        printf("Case %d:\n",cas);
        while(scanf("%s",st)&&st[0]!='E'){
            int x,y;
            scanf("%d%d\n",&x,&y);
            if (st[0]=='M')printf("%lld\n",sum(y)-sum(x-1));
            else {add(x,y-a[x]);a[x]=y;}
        }
    }
    return 0;
}