From d09b9c8dc2d480c91b35c3670cc5bea04e2cc2c0 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Sun, 1 Nov 2026 00:15:19 +0800
Subject: [PATCH] 00:15(160)

---
 subway/subway.cpp | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/subway/subway.cpp b/subway/subway.cpp
index 72149c2..e7d7d6f 100644
--- a/subway/subway.cpp
+++ b/subway/subway.cpp
@@ -4,6 +4,7 @@ int c, n, m, d, q; // 25 500 5e5 20 1e5
 int w[500005];
 vector<pair<int, int>> fri[500505];
 int de[500505];
+int dline[505][505];
 priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
 void dig(int s) {
     memset(de, 0x7f, sizeof(de[0]) * (n + m + 1));
@@ -35,16 +36,32 @@ int main() {
             fri[sta].push_back({ti, m + i});
         }
     }
+    memset(dline, 0x7f, sizeof dline);
+    for(int i = 1; i <= n; ++i) {
+        dig(m + i);
+        for(int j = 1; j <= n; ++j) {
+            dline[i][j] = de[m + j];
+        }
+    }
     while(q--) {
         int x, y;
         scanf("%d%d", &x, &y);
-        dig(x);
-        printf("%d\n", w[x] + w[y] + de[y]);
+        int ans = INT_MAX;
+        for(pair<int, int> i : fri[x]) {
+            for(pair<int, int> j : fri[y]) {
+                ans = min(ans, dline[i.second - m][j.second - m] + i.first + j.first);
+            }
+        }
+        // dig(x);
+        printf("%d\n", w[x] + w[y] + ans);
     }
     return 0;
 }
 /*
+1-15
 g++ subway/subway.cpp -o subway/subway -std=c++14 -O2 -static -Wall && cp subway/subway ~ && chmod +x ~/subway && ~/subway
 
 500 条线路各视为图上的一个点,分别和地铁站连线
+
+考虑优化,注意到可以预处理维护两个地铁线路的最短距离,再枚举起点终点的线路选择
 */
\ No newline at end of file