1 /*
2 题意：给一个n个点,m条边的无向图,要求给m条边定方向,使得每个定点的出入度之差的绝对值小于等于1. 输出任意一种结果
3 图论：一个图，必定存在偶数个奇度顶点。那么从一个奇度定点深搜，当碰到另外一个奇度顶点时结束，这样能保证度数差<=1 3.5 详细解释：http://blog.csdn.net/ZSGG_ACM/article/details/47287681
4 */
5 /************************************************
6 * Author :Running_Time
7 * Created Time :2015-8-5 18:55:37
8 * File Name :F.cpp
9 ************************************************/
10 #pragma comment (linker, "/STACK:1024000000,1024000000")
11 #include <cstdio>
12 #include <algorithm>
13 #include <iostream>
14 #include <sstream>
15 #include <cstring>
16 #include <cmath>
17 #include <string>
18 #include <vector>
19 #include <queue>
20 #include <deque>
21 #include <stack>
22 #include <list>
23 #include <map>
24 #include <set>
25 #include <bitset>
26 #include <cstdlib>
27 #include <ctime>
28 using namespace std;
29
30 #define lson l, mid, rt << 1
31 #define rson mid + 1, r, rt << 1 | 1
32 typedef long long ll;
33 const int MAXN = 1e5 + 10;
34 const int INF = 0x3f3f3f3f;
35 const int MOD = 1e9 + 7;
36 struct Edge {
37 int v, nex, dir;
38 }e[MAXN*6];
39 int head[MAXN];
40 int deg[MAXN];
41 int n, m, tot;
42
43 void init(void) {
44 tot = 0;
45 memset (head, -1, sizeof (head));
46 memset (deg, 0, sizeof (deg));
47 }
48
49 void add_edge(int u, int v) {
50 e[tot].v = v;
51 e[tot].nex = head[u];
52 e[tot].dir = 0;
53 head[u] = tot++;
54 }
55
56 bool DFS(int u) {
57 for (int &i=head[u]; ~i; i=e[i].nex) {
58 int v = e[i].v;
59 int dir = e[i].dir ^ e[i^1].dir;
60 if (dir) continue;
61 e[i].dir = 1;
62 if (deg[v]) {
63 deg[v] = 0; return true;
64 }
65 if (DFS (v)) return true;
66 }
67 return false;
68 }
69
70 void work(void) {
71 for (int i=1; i<=n; ++i) {
72 if (deg[i]) {
73 deg[i] = 0; DFS (i);
74 }
75 }
76 for (int i=1; i<=n; ++i) {
77 while (~head[i]) DFS (i);
78 }
79 for (int i=0; i<tot; i+=2) {
80 if (e[i].dir) puts ("1");
81 else puts ("0");
82 }
83 }
84
85 int main(void) { //HDOJ 5348 MZL‘s endless loop
86 int T; scanf ("%d", &T);
87 while (T--) {
88 init ();
89 scanf ("%d%d", &n, &m);
90 for (int i=1; i<=m; ++i) {
91 int u, v; scanf ("%d%d", &u, &v);
92 deg[u] ^= 1; deg[v] ^= 1;
93 add_edge (u, v); add_edge (v, u);
94 }
95 work ();
96 }
97
98 return 0;
99 }
1 /************************************************
2 * Author :Running_Time
3 * Created Time :2015-8-5 18:55:37
4 * File Name :F.cpp
5 ************************************************/
6 #pragma comment (linker, "/STACK:1024000000,1024000000")
7 #include <cstdio>
8 #include <algorithm>
9 #include <iostream>
10 #include <sstream>
11 #include <cstring>
12 #include <cmath>
13 #include <string>
14 #include <vector>
15 #include <queue>
16 #include <deque>
17 #include <stack>
18 #include <list>
19 #include <map>
20 #include <set>
21 #include <bitset>
22 #include <cstdlib>
23 #include <ctime>
24 using namespace std;
25
26 #define lson l, mid, rt << 1
27 #define rson mid + 1, r, rt << 1 | 1
28 typedef long long ll;
29 const int MAXN = 1e5 + 10;
30 const int INF = 0x3f3f3f3f;
31 const int MOD = 1e9 + 7;
32 struct Edge {
33 int v, nex, vis;
34 }e[MAXN*6];
35 int head[MAXN];
36 int deg[MAXN];
37 int ans[MAXN*6];
38 int n, m, tot;
39
40 void init(void) {
41 tot = 0;
42 memset (head, -1, sizeof (head));
43 memset (deg, 0, sizeof (deg));
44 }
45
46 void add_edge(int u, int v) {
47 e[tot].v = v;
48 e[tot].nex = head[u];
49 e[tot].vis = 0;
50 head[u] = tot++;
51 }
52
53 void DFS(int u) {
54 for (int &i=head[u]; ~i; ) {
55 int v = e[i].v;
56 if (e[i].vis) {
57 i = e[i].nex; continue;
58 }
59 e[i].vis = 1; e[i^1].vis = 1;
60 ans[i>>1] = i & 1;
61 deg[u]--; deg[v]--;
62 i = e[i].nex;
63 DFS (v);
64 }
65 }
66
67 void patch(void) {
68 int pre = -1;
69 for (int i=1; i<=n; ++i) {
70 if (deg[i] & 1) {
71 if (pre == -1) {
72 pre = i;
73 }
74 else {
75 add_edge (pre, i); add_edge (i, pre);
76 deg[pre]++; deg[i]++;
77 pre = -1;
78 }
79 }
80 }
81 }
82
83 void work(void) {
84 patch ();
85 for (int i=1; i<=n; ++i) {
86 if (deg[i]) DFS (i);
87 }
88 for (int i=0; i<m; ++i) printf ("%d\n", ans[i]);
89 }
90
91 int main(void) {
92 int T; scanf ("%d", &T);
93 while (T--) {
94 init ();
95 scanf ("%d%d", &n, &m);
96 for (int i=1; i<=m; ++i) {
97 int u, v; scanf ("%d%d", &u, &v);
98 deg[u]++; deg[v]++;
99 add_edge (u, v); add_edge (v, u);
100 }
101 work ();
102 }
103
104 return 0;
105 }
不太清楚的代码
图论 HDOJ 5348 MZL's endless loop
时间： 2024-08-10 15:10:26