Create 466-count-the-repetitions.js

Author: everthis

466-count-the-repetitions.js

@@ -0,0 +1,39 @@
+/**
+ * @param {string} s1
+ * @param {number} n1
+ * @param {string} s2
+ * @param {number} n2
+ * @return {number}
+ */
+const getMaxRepetitions = function(s1, n1, s2, n2) {
+  let j = 0,
+    i,
+    count = 0,
+    perCycle = 0,
+    firstEnd = -1,
+    lastEnd = -1,
+    nonMatch = 0
+  for (i = 0; i < s1.length * n1; i++) {
+    if (s2[j] === s1[i % s1.length]) {
+      j++
+      nonMatch = 0
+    } else if (++nonMatch >= s1.length) break
+    if (j === s2.length) {
+      count++
+      perCycle++
+      j = 0
+      if (lastEnd !== -1) continue
+      else if (firstEnd === -1) {
+        firstEnd = i
+        perCycle = 0
+      } else if ((i - firstEnd) % s1.length === 0) {
+        let cycleLen = i - firstEnd
+        let remainLen = s1.length * n1 - i - 1
+        let cycles = Math.floor(remainLen / cycleLen)
+        count += cycles * perCycle
+        i += cycles * cycleLen
+      }
+    }
+  }
+  return Math.floor(count / n2)
+}