uvaLA4255 Guess BFS+拓扑排序

算法指南白书

思路:“连续和转化成前缀和之差”

 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <iostream>
 4 #include <algorithm>
 5 #include <vector>
 6 #include <queue>
 7 #include <set>
 8 #include <map>
 9 #include <cstring>
10 #include <math.h>
11 #include <stdlib.h>
12 #include <time.h>
13 using namespace std;
14 const int maxn=50;
15 int T,n;
16 int fa[15];
17 char str[60][60],s[60];
18 int G[15][15];
19 int c[15];
20 vector<int>topo;
21 
22 int findset(int x){//并查集求祖先
23     return fa[x]!=x?fa[x]=findset(fa[x]):x;
24 }
25 bool dfs(int u){//拓扑排序
26     c[u]=-1;
27     for(int i=0;i<=n;i++){
28         if(G[u][i]){
29             if(c[i]<0)
30                 return false;
31             if(c[i]==0) 
32                 dfs(i); 
33         }
34     }
35     c[u]=1;
36     topo.push_back(u);
37     return true;
38 }
39 bool toposort(){
40     topo.clear();
41     memset(c,0,sizeof(c));
42     for(int i=0;i<=n;i++){
43         if(!c[i]){
44             if(!dfs(i))
45                 return false;
46         }
47     }
48     reverse(topo.begin(),topo.end());
49     return true;
50 }
51 int main(){
52     scanf("%d",&T);
53     while(T--){
54         scanf("%d",&n);
55         getchar();
56         scanf("%s",s);
57         int index=0;
58         for(int i=1;i<=n;i++) fa[i]=i;
59         for(int i=1;i<=n;i++){
60             for(int j=i;j<=n;j++){
61                str[i][j]=s[index++];
62                if(str[i][j]=='0')
63                    fa[j]=i-1;//i-1和j同祖先
64             }
65         }
66         memset(G,0,sizeof(G));
67        for(int i=1;i<=n;i++){//sum[i]<sum[j],i到j连一条边
68               for(int j=i;j<=n;j++){
69                   if(str[i][j]=='-')
70                       G[findset(j)][findset(i-1)]=1;
71                if(str[i][j]=='+') 
72                 G[findset(i-1)][findset(j)]=1;
73            }
74        }
75        toposort(); 
76        int sum[15];
77        memset(sum,0,sizeof(sum));
78        int cur=0;
79        for(int i=0;i<=n;i++){//0到。。。赋值
80            sum[topo[i]]=cur++;
81        }
82        for(int i=1;i<=n;i++){
83            sum[i]=sum[findset(i)];
84               if(i>1)
85                printf(" ");
86                printf("%d",sum[i]-sum[i-1]);
87        }
88        printf("\n");
89     }
90     return 0;
91 }
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posted @ 2016-03-24 13:36  yyblues  阅读(258)  评论(0编辑  收藏  举报