[solved] boj22865

HwangJinHa/BOJ/20231026 - 20231030 [ 태호의 장점이 뭔 지 알아? ]/boj22865_가장먼곳.java

@@ -0,0 +1,100 @@
+package study10월5주차월;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.PriorityQueue;
+import java.util.StringTokenizer;
+
+public class boj22865_가장먼곳 {
+    static int n, a, b, c;
+    static int m;
+
+    static int ri = 0;
+    static int[][] results;
+    static ArrayList<int[]>[] graph;
+
+    static PriorityQueue<int[]> closest = new PriorityQueue<>((a, b) -> {
+        if (a[1] == b[1]) {
+            if (a[0] < b[0]) {
+                return -1;
+            }
+            else {
+                return 1;
+            }
+        }
+        else if (a[1] < b[1]) {
+            return -1;
+        }
+        else {
+            return 1;
+        }
+    });
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        n = Integer.parseInt(br.readLine());
+        st = new StringTokenizer(br.readLine());
+        a = Integer.parseInt(st.nextToken()) - 1;
+        b = Integer.parseInt(st.nextToken()) - 1;
+        c = Integer.parseInt(st.nextToken()) - 1;
+        results = new int[3][n];
+        graph = new ArrayList[n];
+        for (int i = 0; i < n; i++) {
+            graph[i] = new ArrayList<>();
+        }
+
+        m = Integer.parseInt(br.readLine());
+        for (int i = 0; i < m; i++) {
+            st = new StringTokenizer(br.readLine());
+            int d = Integer.parseInt(st.nextToken()) - 1;
+            int e = Integer.parseInt(st.nextToken()) - 1;
+            int l = Integer.parseInt(st.nextToken());
+
+            graph[d].add(new int[] {e, l});
+            graph[e].add(new int[] {d, l});
+        }
+        dijk(a);
+        dijk(b);
+        dijk(c);
+        int ansidx = -1;
+        int anslen = Integer.MIN_VALUE;
+        for (int i = 0; i < n; i++) {
+            if (i == a || i == b || i == c)
+                continue;
+            int len = Integer.MAX_VALUE;
+            for (int rr = 0; rr < 3; rr++)
+                len = Math.min(len, results[rr][i]);
+            if (len > anslen) {
+                ansidx = i;
+                anslen = len;
+            }
+        }
+        System.out.println(ansidx + 1);
+    }
+
+    static void dijk(int node) {
+        int[] di = results[ri++];
+        Arrays.fill(di, Integer.MAX_VALUE);
+        di[node] = 0;
+        closest.add(new int[] {node, 0});
+
+        boolean[] fixed = new boolean[n];
+        while (!closest.isEmpty()) {
+            int[] next = closest.poll();
+            if (fixed[next[0]])
+                continue;
+            fixed[next[0]] = true;
+            for (int[] nn : graph[next[0]]) {
+                int len = di[next[0]] + nn[1];
+                if (len < di[nn[0]]) {
+                    di[nn[0]] = len;
+                    closest.add(new int[] {nn[0], len});
+                }
+            }
+        }
+    }
+}