Create Solution.java (Tahanima#91)

Author: Maqsud131

Algorithms/Easy/20_ValidParentheses/Solution.java

@@ -0,0 +1,32 @@
+class Solution {
+    public boolean isValid(String s) {
+        Stack<Character> st = new Stack<Character>(); 
+        
+        for (int i = 0; i < s.length(); i++) {
+            if (s.charAt(i) == '(' || s.charAt(i) == '[' || s.charAt(i) == '{') {
+                st.push(s.charAt(i));
+            } else {
+                char c;
+                
+            if (st.size() > 0) 
+                c = st.pop();
+            else 
+                return false;
+
+            if (s.charAt(i) == ']' && c != '[') 
+                return false;
+
+            if (s.charAt(i) == '}' && c != '{') 
+                return false;
+
+            if (s.charAt(i) == ')' && c != '(') 
+                return false;
+            }
+        }
+            
+        if (st.size() > 0) 
+            return false;
+
+        return true;
+    }
+}