Update 1525-number-of-good-ways-to-split-a-string.js

Author: everthis

1525-number-of-good-ways-to-split-a-string.js

@@ -1,3 +1,36 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+const numSplits = function(s) {
+  const n = s.length
+  const freq = new Map()
+  const prefix = Array(26).fill(0)
+  for(let i = 0; i < n; i++) {
+    if(freq.get(s[i]) == null) freq.set(s[i], 0)
+    freq.set(s[i], freq.get(s[i]) + 1)
+    prefix[i] = freq.size
+  }
+  freq.clear()
+  const suffix = Array(26).fill(0)
+  for(let i = n - 1; i >= 0 ;i--) {
+    if(freq.get(s[i]) == null) freq.set(s[i], 0)
+    freq.set(s[i], freq.get(s[i]) + 1)
+    suffix[i] = freq.size
+  }
+  // console.log(prefix, suffix)
+  let res = 0
+  for(let i = 1; i < n; i++) {
+    if(prefix[i - 1] === suffix[i]) res++
+  }
+  
+  return res
+};
+
+
+// another
+
+
 /**
  * @param {string} s
  * @return {number}