2018-2019 ICPC, NEERC, Southern Subregional Contest (Online Mirror, ACM-ICPC Rules, Teams Preferred)

A. Find a Number

找到一个树，可以被d整除，且数字和为s

记忆化搜索

 1     static class S{
 2         int mod,s;
 3         String str;
 4 
 5         public S(int mod, int s, String str) {
 6             this.mod = mod;
 7             this.s = s;
 8             this.str = str;
 9         }
10     }
11 
12     public static void main(String[] args) {
13         IO io = new IO();
14         int[][]vis=new int[550][5500];
15         int d=io.nextInt(),s=io.nextInt();
16         Queue<S>q=new ArrayDeque<>(10000);
17         q.add(new S(0,0,""));
18         while (!q.isEmpty()){
19             S cur=q.poll();
20             if (cur.mod==0&&cur.s==s){
21                 io.println(cur.str);return;
22             }
23             for (int i = 0; i <=9; i++) {
24                 int mm=(cur.mod*10+i)%d;
25                 int ss=cur.s+i;
26                 if (vis[mm][ss]==0&&ss<=s){
27                     q.add(new S(mm,ss,cur.str+i));
28                     vis[mm][ss]=1;
29                 }
30             }
31         }
32         io.println(-1);
33     }