HDU 1226 BFS

注意密码位数<=500 输出注意十六进制改成字母

要点题目都已说明 ac就好

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<queue>

#define N 5100
#define L(x) (x<<1)
#define R(x) (x<<1|1)
using namespace std;

inline int Max(int a,int b){return a>b?a:b;}
inline int Min(int a,int b){return a<b?a:b;}
int a[20],k,n,c;
int vis[N]; //取模后出现的可能只会是 [0, n-1]
int pre[N];
int num[N];
void BFS(){
	memset(vis, 0, sizeof(vis));
	memset(pre, -1, sizeof(pre));
	queue<int>q;
	int mod;

	for(int i=0;i<k;i++)
	{
		if(!a[i])continue;
		mod = a[i]%n;
		if(!vis[mod])
		{
			vis[mod] = 1;
			num[mod] = a[i];
			q.push(mod);
		}

		if(a[i]%n == 0)
		{if(a[i]<=10)printf("%d\n",a[i]); else printf("%c\n",a[i]-10+'A');return ;}
	}
	bool su =false;
	while(!q.empty() && su == false){
		mod = q.front(); q.pop();
		for(int i=0;i<k;i++)
		{
			int now = (mod*c + a[i])%n;
			if(now == 0){ pre[now] = mod;num[now]=a[i]; su = true; break; }
			if(!vis[now])
			{
				q.push(now);
				vis[now]=1;
				pre[now] = mod;
				num[now] = a[i];
			}
		}
	}

	if(su == false){printf("give me the bomb please\n");return ;}
	int top=0,ans[N];
	for(int i=0; i!=-1;i=pre[i])
		ans[top++]=num[i];
	if(top>500){printf("give me the bomb please\n");return ;}
	for(int i=top-1;i>=0;i--)
		if(ans[i]>=10)
			printf("%c",ans[i] - 10 +'A');
		else
			printf("%d",ans[i]);
	printf("\n");
}

int main(){
	int T;scanf("%d",&T);

	while(T--){
		scanf("%d %d %d",&n,&c,&k);

		for(int i=0;i<k;i++){
			char c=getchar();
			while( !( '0'<=c && c<='9') && !( 'A'<=c && c<='F')) c=getchar();

			if( '0'<=c && c<='9' ) a[i] = c - '0';
			else a[i] = c - 'A' +10;
		}

		sort(a,a+k);

		if(n == 0){
			if(a[0])printf("give me the bomb please\n");
			else printf("0\n");
			continue;
		}

		BFS();
	}
	return 0;
}
/*
3
22 10
3
7 0 1

2 10
1
1

25 16
3
A B C

*/