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1 /*
2 题意：程序从1到n版本升级，正版+正版->正版，正版+盗版->盗版，盗版+盗版->盗版
3 正版+破解版->正版，盗版+破解版->盗版
4 DP：每种情况考虑一遍，递推就行了
5 注意：开long long
6 */
7 #include <cstdio>
8 #include <iostream>
9 #include <algorithm>
10 #include <cstring>
11 #include <cmath>
12 using namespace std;
13
14 const int MAXN = 1e4 + 10;
15 const int INF = 0x3f3f3f3f;
16 struct Node
17 {
18 int u, v, w;
19 char s[10];
20 }node[MAXN];
21 long long dp[MAXN][2];
22
23 bool cmp(Node x, Node y)
24 {
25 if (x.u == y.u) return x.v < y.v;
26 return x.u < y.u;
27 }
28
29 int main(void) //URAL 1741 Communication Fiend
30 {
31 //freopen ("T.in", "r", stdin);
32
33 int n, m;
34 while (scanf ("%d%d", &n, &m) == 2)
35 {
36 for (int i=1; i<=m; ++i)
37 {
38 scanf ("%d %d %d %s", &node[i].u, &node[i].v, &node[i].w, &node[i].s);
39 }
40 sort (node+1, node+1+m, cmp);
41
42 memset (dp, -1, sizeof (dp));
43 dp[1][0] = 0;
44 for (int i=1; i<=m; ++i)
45 {
46 Node a = node[i];
47 if (a.s[0] == ‘L‘)
48 {
49 if (dp[a.u][0] != -1 && (dp[a.v][0] == -1 || dp[a.v][0] > dp[a.u][0] + a.w))
50 {
51 dp[a.v][0] = dp[a.u][0] + a.w;
52 }
53 }
54 else if (a.s[0] == ‘P‘)
55 {
56 if (dp[a.u][0] != -1 && (dp[a.v][1] == -1 || dp[a.v][1] > dp[a.u][0] + a.w))
57 {
58 dp[a.v][1] = dp[a.u][0] + a.w;
59 }
60 if (dp[a.u][1] != -1 && (dp[a.v][1] == -1 || dp[a.v][1] > dp[a.u][1] + a.w))
61 {
62 dp[a.v][1] = dp[a.u][1] + a.w;
63 }
64 }
65 else if (a.s[0] == ‘C‘)
66 {
67 if (dp[a.u][0] != -1 && (dp[a.v][0] == -1 || dp[a.v][0] > dp[a.u][0] + a.w))
68 {
69 dp[a.v][0] = dp[a.u][0] + a.w;
70 }
71 if (dp[a.u][1] != -1 && (dp[a.v][1] == -1 || dp[a.v][1] > dp[a.u][1] + a.w))
72 {
73 dp[a.v][1] = dp[a.u][1] + a.w;
74 }
75 }
76 }
77
78 if (dp[n][0] == -1 && dp[n][1] == -1) puts ("Offline");
79 else
80 {
81 puts ("Online");
82 if (dp[n][0] == -1) printf ("%I64d\n", dp[n][1]);
83 else if (dp[n][1] == -1) printf ("%I64d\n", dp[n][0]);
84 else printf ("%I64d\n", min (dp[n][0], dp[n][1]));
85 }
86 }
87
88 return 0;
89 }
90
91 /*
92 Online
93 Offline
94 */
1 /* 2 WA了4，5发，第一是抄Kuangbin的模板抄错了；第二是选取的INF值太小了 3 以后学习一下最值的选取的方法:) 4 */ 5 #include <cstdio> 6 #include <iostream> 7 #include <algorithm> 8 #include <cstring> 9 #include <vector> 10 #include <cmath> 11 #include <queue> 12 using namespace std; 13 14 const int MAXN = 1e4 + 10; 15 const int INF = 0x3f3f3f3f; 16 const int INFF = 0x7fffffff; 17 const long long inf = ((long long)1<<50); 18 struct Edge 19 { 20 int v, w; 21 int f; 22 Edge (int _v = 0, int _w = 0, int _f = 0) : v (_v), w (_w), f (_f) {} 23 }; 24 bool vis[MAXN]; 25 int cnt[MAXN]; 26 long long d[MAXN][2]; 27 vector<Edge> G[MAXN]; 28 int n, m; 29 30 void add_edge(int u, int v, int w, int f) 31 { 32 G[u].push_back (Edge (v, w, f)); 33 } 34 35 bool SPFA(int s) 36 { 37 memset (cnt, 0, sizeof (cnt)); 38 memset (vis, false, sizeof (vis)); 39 for (int i=1; i<=n; ++i) d[i][0] = d[i][1] = inf; 40 vis[s] = true; d[s][0] = 0; cnt[s] = 1; 41 42 queue<int> Q; Q.push (s); 43 while (!Q.empty ()) 44 { 45 int u = Q.front (); Q.pop (); 46 vis[u] = false; //失误！ 47 for (int i=0; i<G[u].size (); ++i) 48 { 49 int v = G[u][i].v; int w = G[u][i].w; int f = G[u][i].f; 50 if (f == 0) 51 { 52 if (d[v][0] > d[u][0] + w) d[v][0] = d[u][0] + w; 53 } 54 else if (f == 1) 55 { 56 if (d[v][1] > d[u][0] + w) d[v][1] = d[u][0] + w; 57 if (d[v][1] > d[u][1] + w) d[v][1] = d[u][1] + w; 58 } 59 else 60 { 61 if (d[v][0] > d[u][0] + w) d[v][0] = d[u][0] + w; 62 if (d[v][1] > d[u][1] + w) d[v][1] = d[u][1] + w; 63 } 64 if (!vis[v]) 65 { 66 vis[v] = true; Q.push (v); 67 if (++cnt[v] > n) return true; 68 } 69 } 70 } 71 72 return false; 73 } 74 75 int main(void) //URAL 1741 Communication Fiend 76 { 77 //freopen ("T.in", "r", stdin); 78 79 while (scanf ("%d%d", &n, &m) == 2) 80 { 81 for (int i=1; i<=n; ++i) G[i].clear (); 82 for (int i=1; i<=m; ++i) 83 { 84 int u, v, w, f; char s[10]; 85 scanf ("%d %d %d %s", &u, &v, &w, &s); 86 if (s[0] == ‘L‘) f = 0; 87 else if (s[0] == ‘P‘) f = 1; 88 else if (s[0] == ‘C‘) f = -1; 89 add_edge (u, v, w, f); 90 } 91 92 if (!SPFA (1)) 93 { 94 long long ans = min (d[n][0], d[n][1]); 95 if (ans == inf) puts ("Offline"); 96 else {puts ("Online"); printf ("%I64d\n", ans);} 97 } 98 } 99 100 return 0; 101 } 102 103 /* 104 Online 105 Offline 106 */
DP/最短路 URAL 1741 Communication Fiend
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原文地址：http://www.cnblogs.com/Running-Time/p/4495633.html
