UVA 193 Graph Coloring
2015-02-17 15:36
218 查看
You are to write a program that tries to find an optimal coloring for a given graph. Colors are applied to the nodes of the graph and the only available colors are black and white. The coloring of the graph is called optimal if a maximum of nodes is black.
The coloring is restricted by the rule that no two connected nodes may be black.
Figure: An optimal graph with three black nodes
The graph is given as a set of nodes denoted by numbers
,
,
and a set of undirected edges denoted by pairs of node numbers
,
.
The input file contains m graphs. The number m is given on the first line. The first line of each graph contains n and k, the number of nodes and the number of edges, respectively. The following k lines contain
the edges given by a pair of node numbers, which are separated by a space.
The output should consists of 2m lines, two lines for each graph found in the input file. The first line of should contain the maximum number of nodes that can be colored black in the graph. The second line should contain one possible optimal coloring.
It is given by the list of black nodes, separated by a blank.
The coloring is restricted by the rule that no two connected nodes may be black.
Figure: An optimal graph with three black nodes
Input and Output
The graph is given as a set of nodes denoted by numbers ,
,
and a set of undirected edges denoted by pairs of node numbers
,
.
The input file contains m graphs. The number m is given on the first line. The first line of each graph contains n and k, the number of nodes and the number of edges, respectively. The following k lines contain
the edges given by a pair of node numbers, which are separated by a space.
The output should consists of 2m lines, two lines for each graph found in the input file. The first line of should contain the maximum number of nodes that can be colored black in the graph. The second line should contain one possible optimal coloring.
It is given by the list of black nodes, separated by a blank.
Sample Input
1 6 8 1 2 1 3 2 4 2 5 3 4 3 6 4 6 5 6
Sample Output
3 1 4 5 图着色,黑点不能相邻。直接暴力即可。#include<cstdio> #include<cstring> #include<iostream> #include<string> #include<algorithm> #include<math.h> using namespace std; const int maxn = 101; int t, sum, n, m; int f[maxn][maxn], c[maxn], d[maxn]; bool check(int x) { for (int i = 1; i <= f[x][0];i++) if (c[f[x][i]] == c[x]) return false; return true; } void work(int x, int tot) { if (x > n) { if (sum<tot) { sum = tot; tot = 0; for (int i = 1; i <= n; i++) if (c[i] > 0) d[tot++] = i; } return; }; if (tot + n - x + 1 < sum) return; c[x] = 1; if (check(x)) work(x + 1, tot + 1); c[x] = -1; work(x + 1, tot); } int main() { cin >> t; while (t--) { cin >> n >> m; memset(f, 0, sizeof(f)); memset(c, 0, sizeof(c)); for (int i = 0; i < m; i++) { int a, b; cin >> a >> b; f[a][++f[a][0]] = b; f[b][++f[b][0]] = a; } sum = 0; work(1, 0); cout << sum << endl << d[0]; for (int i = 1; i < sum; i++) cout << " " << d[i]; cout << endl; } return 0; }
相关文章推荐
- UVA 193 Graph Coloring 图染色 DFS 数据
- UVa 193 - Graph Coloring
- UVA 193 Graph Coloring
- uva 193 Graph Coloring
- UVa 193 - Graph Coloring
- UVa 193 - Graph Coloring
- UVa 193 & POJ 1419 - Graph Coloring
- uva - 193 Graph Coloring(回溯)
- UVa 193 - Graph Coloring
- UVA 193 Graph Coloring
- uva 193 Graph Coloring(图染色 dfs回溯)
- uva 193 - Graph Coloring
- uva 193 Graph Coloring
- uva 193 Graph Coloring(回溯)
- uva193 - Graph Coloring
- uva 193 Graph Coloring(DFS)
- UVA 193 - Graph Coloring
- uva 193 Graph Coloring
- UVA - 193 Graph Coloring(回溯)
- uva 193 - Graph Coloring