hiho149周

题目链接

坑点：accept和deny的ip可能相同，需加个判断

#include <cstdio>
#include <cstdlib>
#include <vector>
#include <string>
#include <cstring>
#include <iostream>
#define OO 0x0fffffff
#define MIN(a,b) (a<b?a:b)
using namespace std;

struct NODE{
    NODE *left,*right;
    int aid;
    bool accept;
    NODE(){
        aid = -1;
        left = right = NULL;
    }
};
NODE root;
int digits[4];
void add_acl(int id,char *acl,bool accept){
    NODE *ptr = &root;
    for(int i=0;acl[i];i++){
        if(acl[i]=='1') {
            if(ptr->right==NULL) ptr->right = new NODE();
            ptr = ptr->right;
        }
        else{
            if(ptr->left==NULL) ptr->left = new NODE();
            ptr = ptr->left;
        }
    }
    if(ptr->aid<0){
        ptr->aid = id;
        ptr->accept = accept;
    }
}
void parse_ip(char *input,char *output,int len){
    sscanf(input,"%d.%d.%d.%d",digits+0,digits+1,digits+2,digits+3);
    int i,j;
    for(i=0;i<4;i++){
        int td = digits[i];
        for(j=(i+1)*8-1;j>=i*8;j--){
            output[j] = '0'+(td&1);
            td>>=1;
        }
    }
    output[len]='';
}
int main(){
    int m,n,len;
    char type[66],str[66],ip[66];
    scanf("%d%d",&n,&m);
    for(int i=0;i<n;i++){
        cin>>type>>str;
        len = 32;
        std::size_t idx = string(str).find('/');
        if(idx!=std::string::npos){
            str[idx]='';
            len = atoi(str+idx+1);
        }
        parse_ip(str,ip,len);
        add_acl(i,ip,type[0]=='a');
    }
    for(int i=0;i<m;i++){
        cin>>str;
        parse_ip(str,ip,32);
        NODE *ptr = &root;
        int ans = OO;
        bool accept = true;
        int iptr = 0;
        while(ptr){
            if(ptr->aid>=0) {
                if(ptr->aid<ans){
                    ans = ptr->aid;
                    accept = ptr->accept;
                }
            }
            if(ip[iptr]=='1') ptr=ptr->right;
            else ptr=ptr->left;
            iptr++;
        }
        puts(accept?"YES":"NO");
    }
    return 0;
}