代码

#include "router.h"

class RoutingTableEntry_z
{
public:
    unsigned addr;
    unsigned char len;
    unsigned nexthop;
    void set(RoutingTableEntry fr)
    {
        len = fr.len;
        nexthop = fr.nexthop;
        addr = 0;
        for (int i = 0; i < 4; i++)
        {
            addr <<= 8;
            addr |= (fr.addr >> (i*8)) & 255;
        }
    }

}table[827090];

int N;
unsigned Reverse(unsigned addr)
{
    unsigned ret = 0;
    for (int i = 0; i < 4; i++)
    {
        ret <<= 8;
        ret |= (addr >> (i*8)) & 255;
    }
    return ret;
}

void init(int n, int q, const RoutingTableEntry *a) {
    N = n;
    for (int i = 0; i < n; i++)
        table[i].set(a[i]);
}

unsigned query(unsigned addr) {
    int ret = -1;
    for (int l = 0, r = N - 1; l <= r;)
    {
        int mid = (l + r) >> 1;
        if (table[mid].addr == addr)
        {
            ret = mid;
            r = mid - 1;
        }
        else if (table[mid].addr < addr) l = mid + 1;
        else r = mid - 1;
    }
    return ret == -1 ? 0 : table[ret].nexthop;
}

评测结果