uva 12086 - Potentiometers--树状数组

//
//  main.cpp
//  uva 12086 - Potentiometers--树状数组
//
//  Created by XD on 15/9/10.
//  Copyright (c) 2015年 XD. All rights reserved.
//
/*
 树状树组，
 */
#include <iostream>
#include <queue>
#include <stack>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include<vector>
#include <string.h>
#include <algorithm>
#include <set>
#include <map>
#include <cstdio>
#define ll long long
using namespace std ;
const int maxn  =  200000+ 10  ;
ll c[maxn] ;
ll arr[maxn]  ;
int lowerbit(int x)
{
    return x &(-x) ;
}
void updata(int x , ll v )
{
    ll temp = v ;
    v =  v - arr[x] ;
    arr[x] = temp ;
    while (x <=maxn) {
        c[x] += v ; x += lowerbit(x) ;
    }
}
ll sum(int x)
{
    ll ret = 0 ;
    while (x > 0) {
        ret += c[x] ; x-=lowerbit(x) ;
    }
    return ret ;
}
int main(int argc, const char * argv[]) {
    int  n,d,x,y;
    char cmd[10] ;
    int kase = 0 ;
    while (scanf("%d" , &n) , n) {
        memset(arr, 0, sizeof(arr)) ;
        memset(c, 0, sizeof(c)) ;
        if (kase) {
            printf("\n") ;
        }
        for (int i = 1; i <= n ; i++) {
            scanf("%d" , &d) ;
            updata(i, d) ;
        }
        printf("Case %d:\n" ,++kase) ;
        while (scanf("%s" ,cmd)&&cmd[0]!='E') {
            scanf("%d%d" ,&x,&y) ;
            if (cmd[0] == 'M') {
                printf("%lld\n" , sum(y) - sum(x-1)) ;
            }
            else{
                updata(x, y) ;
            }
        }
    }
    return 0;
}