mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
40 lines
803 B
C
40 lines
803 B
C
|
/*
|
||
|
|
作者:千里冰封
|
||
|
|
题目:p3261 小明集邮票
|
||
|
|
*/
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <memory.h>
|
||
|
|
|
||
|
|
int M, N ;
|
||
|
|
unsigned long long cnt ;
|
||
|
|
bool used[6] ;
|
||
|
|
|
||
|
|
void dfs(int now, int total, int last, bool have){
|
||
|
|
if(total > M) return ;
|
||
|
|
// printf("now = %i, total = %i, last = %i, %s, \n", now, total, last, have ? "already have" : "haven`t yet");
|
||
|
|
if(now > N) {
|
||
|
|
int i ;
|
||
|
|
for(i = 1; i <= 5; i++)
|
||
|
|
if(!used[i])
|
||
|
|
break ;
|
||
|
|
if(have && i >= 5)
|
||
|
|
cnt++ ;
|
||
|
|
return ;
|
||
|
|
}
|
||
|
|
now++;
|
||
|
|
for(int i = 1; i <= 5; i++) {
|
||
|
|
bool s = used[i] ;
|
||
|
|
used[i] = true ;
|
||
|
|
dfs(now, total + i, i, last - i == 3 || last - i == -3);
|
||
|
|
used[i] = s ;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char* argv[]){
|
||
|
|
// memset(used, false, sizeof(used[0]));
|
||
|
|
scanf("%i%i", &N, &M) ;
|
||
|
|
dfs(1, 0, -5, false) ;
|
||
|
|
printf("%lld", cnt) ;
|
||
|
|
return 0 ;
|
||
|
|
}
|