Create 1763-longest-nice-substring.js

Author: everthis

1763-longest-nice-substring.js

@@ -0,0 +1,37 @@
+/**
+ * @param {string} s
+ * @return {string}
+ */
+const longestNiceSubstring = function(s) {
+  let res = ''
+  const n = s.length
+  
+  const arr = Array(26).fill(null)
+  for(let i = 0; i < n - 1; i++) {
+    for(let j = i + 1; j < n; j++) {
+      const tmp = s.slice(i, j + 1)
+      if(helper(tmp)) {
+        if(tmp.length > res.length) res = tmp
+      }
+    }
+  }
+  
+  
+  return res
+};
+
+function helper(s) {
+  const arr = Array(26).fill(null)
+  const a = 'a'.charCodeAt(0), A = 'A'.charCodeAt(0)
+  for(let e of s) {
+    const ecode = e.charCodeAt(0)
+    if(arr[ecode - a] === 0 || arr[ecode - A] === 0) continue
+    if(ecode - a < 26 && ecode - a >= 0) arr[ecode - a] = arr[ecode - a] === 1 ? 0 : -1
+    if(ecode - A < 26 && ecode - A >= 0) arr[ecode - A] = arr[ecode - A] === -1 ? 0 : 1
+  }
+  for(let e of arr) {
+    if(e === -1 || e === 1) return false
+  }
+  
+  return true
+}