UVALive 6467 Strahler Order 拓扑排序

 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <stdlib.h>
 4 #include <math.h>
 5 #include <iostream>
 6 #include <stack>
 7 #include <queue>
 8 #include <algorithm>
 9 
10 #define ll long long
11 using namespace std;
12 const int INF = 0x3f3f3f3f;
13 const int MAXN = 8000;
14 int indgree[MAXN], map[MAXN][MAXN], ans[MAXN], cur[MAXN][MAXN];
15 int n;
16 void init(){
17     for(int i = 1; i <= n; ++i){
18         for(int j = 1; j <= n; ++j){
19             map[i][j] = i == j ? 0 : INF;
20         }
21     }
22     memset(indgree, 0, sizeof(indgree));
23     memset(ans, 0, sizeof(ans));
24     memset(cur, 0, sizeof(cur));
25 }
26 
27 void insert_cur(int x, int num){
28     int pos = 1;
29     while(1){
30         if(cur[x][pos] == 0){
31             cur[x][pos] = num;
32             break;
33         }
34         ++pos;
35     }
36 }
37 
38 int sigma_cur(int x){
39     int temp_ans = 0;
40     int Max = -INF;
41     for(int i = 1; cur[x][i] != 0; ++i){
42         if(cur[x][i] > Max) Max = cur[x][i];
43     }
44     int flag = 0;
45     for(int i = 1; cur[x][i] != 0; ++i){
46         if(cur[x][i] == Max)    ++flag;
47     }
48     if(flag >= 2)   ans[x] = ++Max;
49     else if(flag == 1)  ans[x] = Max;
50     return ans[x];
51 }
52 
53 void topsort(){
54     int i, j;
55     while(1){
56         for(i = 1; i <= n; ++i)
57             if(indgree[i] == 0)  break;
58         if(i != n + 1){
59             for(j = 1; j <= n; ++j)
60                 if(map[i][j] == 1){
61                     map[i][j] = 0;
62                     --indgree[j];
63                     insert_cur(j, ans[i]);
64                     if(indgree[j] == 0) ans[j] = sigma_cur(j);
65                 }
66             indgree[i] = -1;//pop i
67         }
68         else break;
69     }
70 }
71 
72 int main(){
73     int i, j, k, p, mm, a, b;
74     scanf("%d",&mm);
75     int numCase = 0;
76     while(mm--){
77         init();
78         scanf("%d%d%d",&k,&n,&p);
79         while(p--){
80             scanf("%d%d",&a,&b);
81             ++indgree[b];
82             map[a][b] = 1;
83         }
84         for(i = 1; i <= n; ++i){
85             if(indgree[i] == 0) ans[i] = 1;
86         }
87         topsort();
88         printf("%d %d\n",++numCase,ans[n]);
89     }
90     return 0;
91 }