题解 | #最短路径问题#
最短路径问题
https://www.nowcoder.com/practice/e372b623d0874ce2915c663d881a3ff2
import java.util.*;
import java.io.*;
public class Main {
int[] he, ne, e, w, p;
int idx;
public static StreamTokenizer in = new StreamTokenizer(new BufferedReader(
new InputStreamReader(System.in)));
public static int nextInt() throws IOException {
in.nextToken();
return (int)in.nval;
}
public Main() {
he = new int[1001];
Arrays.fill(he, -1);
ne = new int[200003];
e = new int[200003];
w = new int[200003];
p = new int[200003];
idx = 0;
}
public void add(int a, int b, int d, int m) {
e[idx] = b;
ne[idx] = he[a];
he[a] = idx;
w[idx] = d;
p[idx] = m;
idx++;
}
public int[] dijkstra(int s, int end) {
int[][] dists = new int[1001][2];
PriorityQueue<int[]> q = new PriorityQueue<>((a, b)->a[1] - b[1]);
for (int i = 1; i < 1001; i++) {
dists[i][0] = 0x3f3f3f3f;
}
boolean[] st = new boolean[1001];
dists[s][0] = 0;
q.add(new int[] {s, dists[s][0]});
while (!q.isEmpty()) {
int[] cur = q.poll();
int cur_p = cur[0];
if (st[cur_p]) continue;
st[cur_p] = true;
for (int i = he[cur_p]; i != -1; i = ne[i]) {
int j = e[i];
if (dists[j][0] > dists[cur_p][0] + w[i]) {
dists[j][0] = dists[cur_p][0] + w[i];
dists[j][1] = dists[cur_p][1] + p[i];
q.add(new int[] {j, dists[j][0]});
}else if(dists[j][0] == dists[cur_p][0] + w[i]){
dists[j][1] = Math.min(dists[cur_p][1] + p[i],dists[j][1]);
}
}
}
return dists[end];
}
public static void main(String[] args) throws IOException {
Main g = new Main();
int n = nextInt();
int m = nextInt();
for (int i = 0; i < m; i++) {
int r1 = nextInt();
int r2 = nextInt();
int r3 = nextInt();
int r4 = nextInt();
g.add(r1, r2, r3, r4);
g.add(r2, r1, r3, r4);
}
int[] ret = g.dijkstra(nextInt(), nextInt());
System.out.print(ret[0] + " " + ret[1]);
}
}
查看12道真题和解析
