hdu 4403 A very hard Aoshu problem

 1 #include<cstdio>
 2 #include<cstring>
 3 #define LL long long
 4 using namespace std;
 5 char str[16];
 6 LL pre[16];
 7 bool add[16];
 8 LL sum;
 9 LL len;
10 LL equ;
11 void dfs(int index);
12 LL left();
13 LL right();
14 int main(void){
15     //freopen("in.txt","r",stdin);
16     //freopen("out_1.txt","w",stdout);
17     scanf("%s",str);
18     while(strcmp(str,"END")){
19         len=strlen(str);
20         memset(pre,0,sizeof(pre));
21         pre[0]=str[0]-‘0‘;
22         for(int i=1;i<len;++i)
23             pre[i]=pre[i-1]+str[i]-‘0‘;
24         sum=0;
25         for(equ=1;equ<len;++equ){
26             memset(add,0,sizeof(add));
27             dfs(1);
28         }
29         printf("%I64d\n",sum);
30         scanf("%s",str);
31     }
32 }
33 LL left(){
34     LL s=0;
35     LL t=0;
36     for(LL i=0;i!=equ;++i){
37         if(!add[i]){
38             t=t*10+str[i]-‘0‘;
39         }else{
40             s+=t;
41             t=str[i]-‘0‘;
42         }
43     }
44     s+=t;
45     return s;
46 }
47 LL right(){
48     LL s=0;
49     LL t=0;
50     for(LL i=equ;i<len;++i){
51         if(!add[i]){
52             t=t*10+str[i]-‘0‘;
53         }else{
54             s+=t;
55             t=str[i]-‘0‘;
56         }
57     }
58     s+=t;
59     return s;
60 }
61 void dfs(int index){
62     LL l=left();
63     LL r=right();
64     if(l==r){
65         sum++;
66     }else{ //剪枝
67         if(l<pre[len-1]-pre[equ-1])
68             return;
69         if(r<pre[equ-1])
70             return;
71     }
72     if(index>=len)
73         return;
74     for(LL i=index;i<len;++i){
75         if(i!=equ){
76             add[i]=1;
77             dfs(i+1);
78             add[i]=0;
79         }
80     }
81 }