Merge pull request #117 from aggarwalmayank/patch-2

balanced parenthesis using stack in C

Data Structures/stack/balanced parenthesis using stack in C

@@ -0,0 +1,89 @@
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#define size 100
+
+struct node
+{
+    char data;
+    struct node* link;
+};
+int c=0;	// c used as counter to check if stack is empty or not
+struct node * head;	 //declaring head pointer globally assigned to NULL
+
+void push(char x) //function for pushing
+{
+struct node *p,*temp; 
+    temp=(struct node*)malloc(sizeof(struct node));
+    temp->data=x;
+    if(head==NULL)	//will be execute only one time i.e, 1st time push is called
+    {
+        head=temp;
+        p=head;
+        p->link=NULL;
+        c++;
+    }
+    else
+    {
+        temp->link=p;
+        p=temp;
+        head=p;
+        c++;
+    }
+    
+}
+char pop(void)	//function for pop
+{
+    char x;
+    struct node*p=head;
+    x=p->data;
+    head=p->link;
+    free(p);
+    c--;
+    return x;
+    
+}
+
+int isBalanced(char *s) {		   
+    int i=0;char x;
+ while(s[i]!='\0')	//loop for covering entire string of brackets
+ {
+     if(s[i]=='{'||s[i]=='('||s[i]=='[') //if opening bracket then push
+         push(s[i]);
+        else 
+        {
+            if(c<=0)			//i.e, stack is empty as only opening brackets are added to stack
+                return 0;
+        
+            
+               x=pop();			
+                if( x=='{'&&s[i]!='}')	
+                    return 0;
+                if(x=='['&&s[i]!=']')
+                    return 0;
+                if(x=='('&&s[i]!=')')
+                    return 0 ;
+        }i++;       
+    }			
+      if(c==0)		//at end if stack is empy which means whole process has been performed correctly so retuen 1
+          return 1;
+        else
+            return 0;
+}
+
+int main() {
+    int t;
+    scanf("%d",&t);
+    for(int a0 = 0; a0 < t; a0++){
+        char s[size];
+int result;
+        scanf("%s",s);
+        result = isBalanced(s);
+if(result==1)
+printf("\nYES");
+else       
+ printf("\nNO");
+		
+    }
+    return 0;
+}