Update 1377-frog-position-after-t-seconds.js

Author: everthis

1377-frog-position-after-t-seconds.js

@@ -1,3 +1,44 @@
+/**
+ * @param {number} n
+ * @param {number[][]} edges
+ * @param {number} t
+ * @param {number} target
+ * @return {number}
+ */
+const frogPosition = function (n, edges, t, target) {
+  const m = new Map()
+  for(let e of edges) {
+    const [from, to] = e
+    if(!m.has(from - 1)) m.set(from - 1, [])
+    if(!m.has(to - 1)) m.set(to - 1, [])
+    m.get(from - 1).push(to - 1)
+    m.get(to - 1).push(from - 1)
+  }
+  const visited = new Set()
+  visited.add(0)
+  const q = [0]
+  const res = [1]
+  while(q.length && t-- > 0) {
+    for(let size = q.length; size > 0 ; size--) {
+      const u = q.shift()
+      let count = 0
+      for(let e of (m.get(u) || [])) {
+        if(!visited.has(e)) count++
+      }
+      for(let e of (m.get(u) || [])) {
+        if(visited.has(e)) continue
+        q.push(e)
+        visited.add(e)
+        res[e] = res[u] / count
+      }
+      if(count > 0) res[u] = 0      
+    }
+  }
+  return res[target - 1] || 0
+}
+
+// another
+
 /**
  * @param {number} n
  * @param {number[][]} edges