密码机

树状数组

#include<bits/stdc++.h>
using namespace std;
int x,y,c[200005];
char str[20];
int inline read(){
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
        ch=getchar();
    while(ch>='0'&&ch<='9'){
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f;
}
inline void add(int x,int y){
    while (x<=20005){
        c[x]^=y;
        x+=x&-x;
    }
    return;
}
inline int ask(int x){
    int sum=0;
    while (x){
        sum^=c[x];
        x-=x&-x;
    }
    return sum;
}
int main(){
    while (~scanf("%s",str)){
        if (str[0]=='A'||str[0]=='R'){
            x=read();
            add(x,x);
        }
        else if (str[0]=='X'){
            x=read();
            y=read();
            if (x>y)
                printf("0\n");
            else 
                printf("%d\n",ask(x-1)^ask(y));
        }
        else return 0;
        scanf("\n");
    }
    return 0;
}