第一道树状数组。题很水。继续下一道。。。让我疑惑在这。。。
#include<cstdio>
#include<iostream>
#include<string>
#include<cstring>
using namespace std;
int n;
int a[50010],p[50010];//a树状数组
int lowb(int t){return t&(-t);}
void add(int i,int v){
for(;i<=n;a[i]+=v,i+=lowb(i)); //尼玛 i < n 为毛不对？
}
int sum(int i){
int s=0;
for(;i>0;s+=a[i],i-=lowb(i));
return s;
}
int getsum(int x1,int x2){return sum(x2)-sum(x1-1);}
int main(){
int N=1;
int i,l,r,T;
char ch[10];
cin>>T;
while(T--){
memset(p,0,sizeof(p));
memset(a,0,sizeof(a));
printf("Case %d:\n",N++);
cin>>n;
for(i=1;i<=n;i++){
scanf("%d",&p[i]);
add(i,p[i]);
}
while(~scanf("%s",ch)){
if(!strcmp(ch,"End")) break;
scanf("%d%d",&l,&r);
if(!strcmp(ch,"Add")) add(l,r);
if(!strcmp(ch,"Sub")) add(l,-r);
if(!strcmp(ch,"Query")) printf("%d\n",getsum(l,r));
}
}
return 0;
}