Create 392-is-subsequence.js

Author: everthis

392-is-subsequence.js

@@ -0,0 +1,28 @@
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+const isSubsequence = function(s, t) {
+  let ti = 0
+  let tmp = 0
+  for (let i = 0; i < s.length; i++) {
+    if ((tmp = chk(t, ti, s.charAt(i))) === -1) {
+      return false
+    } else {
+      ti = tmp + 1
+    }
+  }
+
+  return true
+}
+
+function chk(str, start, target) {
+  let idx = start
+  for (let i = start; i < str.length; i++) {
+    if (str.charAt(i) === target) {
+      return i
+    }
+  }
+  return -1
+}