Merge pull request #187 from TanyaKhandelwal/master

Balanced parentheses #166

Author: ashokdey

src/_Problems_/balanced-parentheses.test.js

@@ -0,0 +1,21 @@
+const { parentheses } = require('.');
+
+describe('Parentheses', () => {
+  it('Should return true only when matching brackets are there', () => {
+    expect(parentheses("{[()]})").toEqual('Balanced');
+  });
+
+  it('Should return false when matching brackets are not there', () => {
+    expect(parentheses("{[()}])").toEqual('UnBalanced');
+  });
+  it('Should return true only when matching brackets are there', () => {
+    expect(parentheses("{()})").toEqual('Balanced');
+  });
+
+  it('Should return false when matching brackets are not there', () => {
+    expect(parentheses("{[}])").toEqual('UnBalanced');
+  });
+
+
+
+});

src/_Problems_/index.js

@@ -0,0 +1,36 @@
+// FIND BALANCED PARENTHESIS
+// FOR '[{()}]' ---->>>>  BALANCED
+// FOR '[{()]' ---->>>>  UNBALANCED
+// Time complexity : O(n)  n is the length of the string provided.
+
+
+function parentheses(s) {
+    if(typeof s !== "string" || s.length % 2 !== 0) return false;
+    let i = 0;
+    let arr = [];
+    while(i<s.length) {
+        if(s[i]=== "{" || s[i]=== "(" || s[i]=== "[") {
+           arr.push(s[i]);
+        }
+        else if(s[i] === "}" && arr[arr.length-1] === "{") {
+            arr.pop();
+        }
+        else if(s[i] === ")" && arr[arr.length-1] === "(") {
+            arr.pop();
+        }
+        else if(s[i] === "]" && arr[arr.length-1] === "[") {
+            arr.pop();
+        }
+        return "Unbalanced";
+
+        i++
+    }
+    if (arr.length === 0)
+    return "Balanced";
+};
+
+
+
+module.exports = {
+  parentheses,
+  };