代码

#include "router.h"
#include <arpa/inet.h>
#include <unordered_map>
std::unordered_map<unsigned,unsigned> Map[33];

void init(int n,int q,const RoutingTableEntry *a){
    const RoutingTableEntry *tmp=nullptr;
    for(int i=0;i<n;i++){
        tmp = a + i;
        Map[tmp->len][htonl(tmp->addr)] = tmp->nexthop;
    }

}

unsigned query(unsigned addr){
    addr = htonl(addr);
    for(int len = 32;len>=0;len--){
        if(Map[len].count(addr))
            return Map[len][addr];
        addr &=~(1u << (32-len));
    }
    return 0;
}

评测结果