代码

//#define Debug 
#ifndef Debug
#include "router.h"
#endif
#ifdef Debug
typedef struct {
    unsigned addr;
    unsigned char len;
    char pad[3];  // Padding for memory alignment
    unsigned nexthop;
} __attribute__((packed)) RoutingTableEntry;
#endif

#include <cstdlib>
unsigned int ans=-1;
int maxlen=-1;
int n;
int q;
const RoutingTableEntry *a;

void init(int _n, int _q, const RoutingTableEntry *_a) {
	n=_n;
	q=_q;
	a=_a;
}

inline unsigned reverse(unsigned x){
	return ((x&0b11111111000000000000000000000000)>>24)
	      +((x&0b00000000111111110000000000000000)>>8)
	      +((x&0b00000000000000001111111100000000)<<8)
	      +((x&0b00000000000000000000000011111111)<<24);
}

unsigned query(unsigned addr) {


	for (int i=0;i<n;i++){
		if (((reverse(addr)>>(32-int(a[i].len)))==(reverse(a[i].addr)>>(32-int(a[i].len))))&&(int(a[i].len)>maxlen)){
			maxlen=a[i].len;
			ans=a[i].nexthop;
		}
	}	
	return ans;
}

评测结果