add js solution[387]

Author: limbowandering

solution/387.First Unique Character in a String/Solution.js

@@ -0,0 +1,49 @@
+const firstUniqChar2 = function(s){
+  let arr = {};
+  for(let i = 0; i < s.length; i++){
+    // console.log(arr[s[i]]);
+    if(arr[s[i]]){
+      arr[s[i]]++;
+    }else{
+      arr[s[i]] = 1; 
+    }
+  }
+  let keys = Object.keys(arr);
+  for(let i = 0; i < keys.length; i++){
+    if(arr[keys[i]] !== 1){
+      keys.splice(i,1);
+      i--;
+    }
+  }
+  for(let i = 0; i < s.length; i++){
+    for(let j = 0; j < keys.length; j++){
+      if(s[i] === keys[j]){
+        return i;
+      }
+    }
+  }
+  return -1;
+}
+
+const firstUniqChar = function(s){
+  let hashTable = {};
+  let arr = [];
+
+  for(let i = 0; i < s.length; i++){
+    let c = s.charAt(i);
+    if(!hashTable.hasOwnProperty(c)){
+      hashTable[c] = i;
+      arr.push(i);
+    }else{
+      if(hashTable[c] !== null){
+        let val = hashTable[c];
+        let index = arr.indexOf(val);
+        arr.splice(index,1);
+        hashTable[c] = null;
+      }
+    }
+
+  }
+
+  return arr.length ? arr[0] : -1;
+}