poj 1416 -- Shredding Company

 1 /*======================================================================
 2  *           Author :   kevin
 3  *         Filename :   ShreddingCompany.cpp
 4  *       Creat time :   2014-08-07 11:33
 5  *      Description :
 6  ========================================================================*/
 7 #include <iostream>
 8 #include <algorithm>
 9 #include <cstdio>
10 #include <cstring>
11 #include <cstdlib>
12 #include <queue>
13 #include <cmath>
14 #define clr(a,b) memset(a,b,sizeof(a))
15 #define M
16 using namespace std;
17 int t,n,m,ans;
18 char str[10];
19 int cut[10],bestcut[10],cntmax;
20 /*---切纸操作,每次切两刀,但a刀是重复的---*/
21 int CutPaper(int a,int b,int sum)         /*sum表示当前数*/
22 {
23     int as = pow(10,n-a);
24     sum = sum-(m % as);
25     if(sum <= t){                         /*a刀切完后判断当前sum是否满足条件*/
26         cut[a] = 1;                       /*满足标记此刀*/
27     }
28     int s = 0;
29     for(int i = a; i < b; i ++){
30         s = s*10 + (str[i] - ‘0‘);
31     }
32     sum += s;
33     if(sum <= t){                         /*b刀切完后判断当前sum是否满足条件*/
34         cut[b] = 1;                       /*满足标记*/
35     }
36     s = 0;
37     for(int i = b; i < n; i++){           /*计算剩余部分*/
38         s = s*10 + (str[i] - ‘0‘);
39     }
40     sum += s;
41     return sum;
42 }
43 /*-------------------深搜函数---------------------*/
44 void DFS(int id,int sum)
45 {
46     if(id == n) return ;                           /*id代表当前刀的位置，若等于n说明切到了最后*/
47     for(int i = id+1; i <= n-1; i++){
48         int temp = CutPaper(id,i,sum);
49         if(temp <= t && temp > ans){               /*若此次切纸操作满足要求*/
50             cntmax = 0;                            /*将标记最大值次数置零*/
51             ans = temp;                            /*更新最大值*/
52             memcpy(bestcut,cut,sizeof(bestcut));   /*拷贝当前最优结果到bestcut*/
53         }
54         else if(temp <= t && temp == ans){         /*若当前最优结果再次出现*/
55             cntmax++;
56         }
57         DFS(i,temp);
58         cut[id] = 0; cut[i] = 0;                   /*回溯必须*/
59     }
60 }
61 int main(int argc,char *argv[])
62 {
63     while(scanf("%d%s",&t,str)!=EOF){
64         if(t == 0 && str[0] == ‘0‘){
65             break;
66         }
67         m = atoi(str);
68         n = strlen(str);
69         if(t >= m){
70             printf("%d %d\n",m,m);
71             continue;
72         }
73         ans = -1;
74         cntmax = 0;
75         DFS(0,m);
76         if(ans == -1){
77             printf("error\n");
78         }
79         else if(cntmax >= 1){
80             printf("rejected\n");
81         }
82         else{
83             printf("%d",ans);
84             for(int i = 0; i < n; i++){
85                 if(bestcut[i]){
86                     printf(" ");
87                 }
88                 printf("%c",str[i]);
89             }
90             printf("\n");
91         }
92         clr(str,0);
93     }
94     return 0;
95 }