Create 1129-shortest-path-with-alternating-colors.js

Author: everthis

1129-shortest-path-with-alternating-colors.js

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+/**
+ * @param {number} n
+ * @param {number[][]} red_edges
+ * @param {number[][]} blue_edges
+ * @return {number[]}
+ */
+const shortestAlternatingPaths = function(n, red_edges, blue_edges) {
+  let d = new Array(n * 2).fill(Number.MAX_SAFE_INTEGER)
+  let queue = []
+  d[0] = d[n] = 0
+  queue.push(0)
+  queue.push(n)
+  while (queue.length) {
+    let cur = queue.shift()
+    if (cur < n) {
+      for (let r of red_edges) {
+        if (r[0] == cur && d[r[1] + n] > d[cur] + 1) {
+          d[r[1] + n] = d[cur] + 1
+          queue.push(r[1] + n)
+        }
+      }
+    } else {
+      for (let b of blue_edges) {
+        if (b[0] == cur - n && d[b[1]] > d[cur] + 1) {
+          d[b[1]] = d[cur] + 1
+          queue.push(b[1])
+        }
+      }
+    }
+  }
+  let res = new Array(n).fill(-1)
+  for (let i = 0; i < n; i++) {
+    res[i] =
+      Math.min(d[i], d[i + n]) == Number.MAX_SAFE_INTEGER
+        ? -1
+        : Math.min(d[i], d[i + n])
+  }
+  return res
+}