feat: 332. Reconstruct Itinerary : 欧拉路径

Author: upupming

leetcode/残酷刷题/332. Reconstruct Itinerary.ts

@@ -0,0 +1,32 @@
+/*
+        -> D -> E
+A -> B <-> F
+       <-> G
+[["JFK","BBB"],["BBB","FFF"],["FFF","BBB"],["BBB","GGG"],["GGG","BBB"],["BBB","DDD"],["DDD","EEE"]]
+*/
+function findItinerary (tickets: string[][]): string[] {
+  const e: Record<string, string[]> = {}
+  for (const [f, t] of tickets) {
+    e[f] ??= [], e[f].push(t)
+  }
+  for (const v of Object.values(e)) v.sort((a, b) => a < b ? 1 : -1)
+  console.log(e)
+  const dfs = (x: string) => {
+    const paths: string[][] = []
+    // e: {BBB: [ 'GGG', 'FFF', 'DDD' ],}
+    // 最多循环两次，第一次是 DE，第二次是 FBGB
+    while (e[x]?.length) {
+      // 走一个字典序最小的 y
+      const y = e[x].pop()!
+      paths.push(dfs(y))
+    }
+    const ans = [x]
+    console.log(x, paths)
+    while (paths.length) {
+      const p = paths.pop()!
+      ans.push(...p)
+    }
+    return ans
+  }
+  return dfs('JFK')
+};

leetcode/残酷刷题/README.md

@@ -26,6 +26,7 @@
         - [表达式求值](#表达式求值)
         - [状态机](#状态机)
         - [链表](#链表)
+        - [欧拉路径](#欧拉路径)
     - [Links](#links)
 
 ## Problems
@@ -179,6 +180,10 @@
 - 2074. Reverse Nodes in Even Length Groups
 - 143. Reorder List
 
+### 欧拉路径
+
+- 332. Reconstruct Itinerary
+
 ## Links
 
 - https://wisdompeak.github.io/lc-score-board/