-
Notifications
You must be signed in to change notification settings - Fork 0
/
Dijkstra.java
115 lines (98 loc) · 2.71 KB
/
Dijkstra.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
package shortestPath;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.StringTokenizer;
class Graph{
int dest;
int weight;
public Graph(int dest, int weight){
this.dest = dest;
this.weight = weight;
}
@Override
public boolean equals(Object obj){
Graph otherG = (Graph)obj;
if(otherG.dest == this.dest)
return true;
return false;
}
}
public class Dijkstra {
public static void main(String[] args) throws IOException {
final int MAXVALUE = 10000000;
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
StringTokenizer st = new StringTokenizer(br.readLine());
int V = Short.parseShort(st.nextToken()); //vertex
int E = Integer.parseInt(st.nextToken()); //edge
int U = Short.parseShort(br.readLine()); //start
ArrayList<Graph> weights[] = new ArrayList[V + 1];
int dist[] = new int[V + 1];
boolean isFixed[] = new boolean[V + 1]; //S
for (int i = 1; i <= V; i++){
weights[i] = new ArrayList<Graph>();
dist[i] = MAXVALUE;
}
for (int i = 0; i < E; i++) {
st = new StringTokenizer(br.readLine());
int u = Integer.parseInt(st.nextToken());
int v = Integer.parseInt(st.nextToken());
int w = Byte.parseByte(st.nextToken());
Graph newG = new Graph(v, w);
int index = weights[u].indexOf(newG);
if(index > -1){
if(weights[u].get(index).weight > newG.weight)
weights[u].set(index, newG);
} else
weights[u].add(new Graph(v, w));
}
//init values
dist[U] = 0;
isFixed[U] = true;
for (int i = 0; i < weights[U].size(); i++){
dist[weights[U].get(i).dest] = weights[U].get(i).weight;
}
/*
* dijkstra
* */
for (int i = 0; i < V - 1; i++) {
// select next
int minDist = MAXVALUE + 1;
int minV = 0;
for (int j = 1; j <= V; j++) {
if(!isFixed[j]){
if(minDist > dist[j]){
minDist = dist[j];
minV = j;
}
}
}
U = minV;
isFixed[U] = true;
//dist °è»ê
for (int j = 0; j < weights[U].size(); j++) {
int dest = weights[U].get(j).dest;
if(!isFixed[dest]){
dist[dest] = Math.min(dist[dest], dist[U] + weights[U].get(j).weight);
}
}
}
//output
for (int i = 1; i <= V; i++) {
if(dist[i] == 0)
bw.write("0\n" );
else if(dist[i] == MAXVALUE)
bw.write("INF\n");
else
bw.write(dist[i] + "\n");
}
br.close();
bw.close();
}
}