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MyStack.java
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523 lines (522 loc) · 15.7 KB
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import java.util.Stack;
public class MyStack {
static void copy(Stack<Integer> s1){
Stack<Integer> s2 = new Stack<>();
while(!s1.isEmpty()){
s2.push(s1.pop());
}
Stack<Integer> ans = new Stack<>();
while(s2.size()>0){
ans.push(s2.pop());
}
System.out.println(ans);
}
static void insertAt(Stack<Integer> s1,int indx,int element){
Stack<Integer> s2 = new Stack<>();
while(s1.size()>indx){
s2.push(s1.pop());
}
s1.push(element);
while(s2.size()>0){
s1.push(s2.pop());
}
System.out.println(s1);
}
static void insertArray(Stack<Integer> s1,int indx,int element){
int arr[]=new int[s1.size()];
int count=0;
while(s1.size()>indx){
arr[count++]=s1.pop();
}
s1.push(element);
for(int i=count-1;i>=0;i--){
s1.push(arr[i]);
}
System.out.println(s1);
}
static void reverse(Stack<Integer> s1){
Stack<Integer> s2=new Stack<>();
while(s1.size()>0){
System.out.print(s2.push(s1.pop())+" ");
}
}
static void reverseRec(Stack<Integer> s1){
if(s1.size()==0)return;
int x=s1.pop();
System.out.print(x+" ");
reverse(s1);
s1.push(x);
}
static void print(Stack<Integer> s1){
Stack<Integer> s2=new Stack<>();
while(s1.size()>0){
s2.push(s1.pop());
}
while(s2.size()>0){
System.out.print(s1.push(s2.pop())+" ");
}
}
static void printRec(Stack<Integer> s1){
if(s1.size()==0)return;
int x=s1.pop();
printRec(s1);
System.out.print(x+" ");
s1.push(x);
}
static void insertRec(Stack<Integer> s1,int indx,int element){
if(s1.size()==indx){
s1.push(element);
return;
}
int x=s1.pop();
insertRec(s1,indx,element);
s1.push(x);
}
static void reverseStack(Stack<Integer> s1){
if(s1.size()==1)return;
int x=s1.pop();
reverseStack(s1);
insertAtBottomRec(s1, x);
}
static void insertAtBottomRec(Stack<Integer> s,int element){
if(s.size()==0){
s.push(element);
return;
}
int temp=s.pop();
insertAtBottomRec(s, element);
s.push(temp);
}
static void removeIndxRec(Stack<Integer> s,int indx){
if(s.size()==indx+1){
s.pop();
return;
}
int temp=s.pop();
removeIndxRec(s, indx);
s.push(temp);
}
static void removeIndx(Stack<Integer> s1,int indx){
Stack<Integer> s2=new Stack<>();
while(s1.size()>indx+1){
s2.push(s1.pop());
}
s1.pop();
while(s2.size()>0){
s1.push(s2.pop());
}
}
static void reverseUsingArray(Stack<Integer> s1){
int arr[]=new int[s1.size()];
int count=0;
while(s1.size()>0)arr[count++]=s1.pop();
for(int i=0;i<count;i++)s1.push(arr[i]);
}
static void reverseUsing3Stack(Stack<Integer> s1){
Stack<Integer> s2=new Stack<>();
Stack<Integer> s3=new Stack<>();
while(s1.size()>0)s2.push(s1.pop());
while(s2.size()>0)s3.push(s2.pop());
while(s3.size()>0)s1.push(s3.pop());
}
public static int minNum(String str){
int ans=0;
Stack<Character> stk=new Stack<>();
for(char x:str.toCharArray()){
if(x=='(')stk.push(x);
else{
if(stk.size()>0)stk.pop();
else ans++;
}
}
return ans+stk.size();
}
public static void removeConsec(int arr[]){
Stack<Integer> stk=new Stack<>();
for(int i=0;i<arr.length;i++){
if(stk.size()==0)stk.push(arr[i]);
else if(i<arr.length-1){
if(arr[i]==stk.peek()){
if(arr[i]!=arr[i+1]){
stk.pop();
}
}else stk.push(arr[i]);
}else{
if(arr[i]!=arr[i-1])stk.push(arr[i]);
else stk.pop();
}
}
System.out.println(stk);
}
public static void nextGreater(int[] arr) {
Stack<Integer> st=new Stack<>();
st.push(arr[arr.length-1]);
arr[arr.length-1]=-1;
for(int i=arr.length-2;i>=0;i--){
int temp=arr[i];
while(st.size()>0&&st.peek()<arr[i])st.pop();
if(st.size()==0)arr[i]=-1;
else arr[i]=st.peek();
st.push(temp);
}
MyArrays.printArray(arr);
}
public static void prevGreater(int arr[]){
Stack<Integer> st=new Stack<>();
st.push(arr[0]);
arr[0]=-1;
for(int i=1;i<arr.length;i++){
int temp=arr[i];
while(st.size()>0&&st.peek()<arr[i])st.pop();
if(st.size()==0)arr[i]=-1;
else arr[i]=st.peek();
st.push(temp);
}
MyArrays.printArray(arr);
}
public static void nextGreater2(int[] arr) {
int ans[] = new int[arr.length];
Stack<Integer> stk = new Stack<>();
stk.push(0);
for(int i = 1; i < arr.length; i++) {
while(stk.size() > 0 && arr[i] > arr[stk.peek()])
{ ans[stk.pop()] = arr[i];
}
stk.push(i);
}
while(stk.size() > 0) {
ans[stk.pop()] = -1;
}
MyArrays.printArray(ans);
}
public static void infixOperator(String s) {
Stack<Integer> val=new Stack<>();
Stack<Character> op=new Stack<>();
for(char x:s.toCharArray()){
if(x-'0'>=0&&x-'0'<=9)val.push(x-'0');
else if(op.size()==0||x=='('||op.peek()=='(')op.push(x);
else if(x==')'){
while(op.peek()!='('){
int v2=val.pop();
int v1=val.pop();
if(op.peek()=='+')val.push(v1+v2);
else if(op.peek()=='-')val.push(v1-v2);
else if(op.peek()=='*')val.push(v1*v2);
else if(op.peek()=='/')val.push(v1/v2);
op.pop();
}
op.pop();
}
else{
if(x=='+'||x=='-'||
(x=='*'&&(op.peek()=='*'||op.peek()=='/'))||
(x=='/'&&(op.peek()=='*'||op.peek()=='/'))){
int v2=val.pop();
int v1=val.pop();
if(op.peek()=='+')val.push(v1+v2);
else if(op.peek()=='-')val.push(v1-v2);
else if(op.peek()=='*')val.push(v1*v2);
else if(op.peek()=='/')val.push(v1/v2);
op.pop();
}
op.push(x);
}
}
while(val.size()>1){
int v2=val.pop();
int v1=val.pop();
char x=op.pop();
if(x=='+')val.push(v1+v2);
else if(x=='-')val.push(v1-v2);
else if(x=='*')val.push(v1*v2);
else if(x=='/')val.push(v1/v2);
}
System.out.println(val.pop());
}
public static void prefix(String s){
Stack<Character> op=new Stack<>();
Stack<String> val=new Stack<>();
for(char x:s.toCharArray()){
if(Character.isDigit(x))val.push(""+x);
else if(op.size()==0||x=='('||op.peek()=='(')op.push(x);
else if(x==')'){
while(op.peek()!='('){
String v2=val.pop();
String v1=val.pop();
char y=op.peek();
val.push(y+v1+v2);
op.pop();
}
op.pop();
}
else{
if(x=='+'||x=='-'||
(x=='*'&&(op.peek()=='*'||op.peek()=='/'))||
(x=='/'&&(op.peek()=='*'||op.peek()=='/'))){
String v2=val.pop();
String v1=val.pop();
char y=op.peek();
val.push(y+v1+v2);
op.pop();
}
op.push(x);
}
}
while(val.size()>1){
String v2=val.pop();
String v1=val.pop();
char y=op.pop();
val.push(y+v1+v2);
}
System.out.println(val.pop());
}
public static void postfix(String s){
Stack<Character> op=new Stack<>();
Stack<String> val=new Stack<>();
for(char x:s.toCharArray()){
if(Character.isDigit(x))val.push(""+x);
else if(op.size()==0||x=='('||op.peek()=='(')op.push(x);
else if(x==')'){
while(op.peek()!='('){
String v2=val.pop();
String v1=val.pop();
char y=op.peek();
val.push(v1+v2+y);
op.pop();
}
op.pop();
}
else{
if(x=='+'||x=='-'||
(x=='*'&&(op.peek()=='*'||op.peek()=='/'))||
(x=='/'&&(op.peek()=='*'||op.peek()=='/'))){
String v2=val.pop();
String v1=val.pop();
char y=op.peek();
val.push(v1+v2+y);
op.pop();
}
op.push(x);
}
}
while(val.size()>1){
String v2=val.pop();
String v1=val.pop();
char y=op.pop();
val.push(v1+v2+y);
}
System.out.println(val.pop());
}
public static void postFixToInfix(String str) {
Stack<Integer> val=new Stack<>();
for(char x:str.toCharArray()){
if(Character.isDigit(x))val.push(x-'0');
else{
int val2=val.pop();
int val1=val.pop();
if(x=='+')val.push(val1+val2);
else if(x=='-')val.push(val1-val2);
else if(x=='*')val.push(val1*val2);
else if(x=='/')val.push(val1/val2);
}
}
System.out.println(val.pop());
}
public static void preFixToInfix(String str) {
Stack<Integer> val=new Stack<>();
for(int i=str.length()-1;i>=0;i--){
char x=str.charAt(i);
if(Character.isDigit(x))val.push(x-'0');
else{
int val1=val.pop();
int val2=val.pop();
if(x=='+')val.push(val1+val2);
else if(x=='-')val.push(val1-val2);
else if(x=='*')val.push(val1*val2);
else if(x=='/')val.push(val1/val2);
}
}
System.out.println(val.pop());
}
public static void prefixToPostfix(String str) {
Stack<String> val=new Stack<>();
for(int i=str.length()-1;i>=0;i--){
char x=str.charAt(i);
if(Character.isDigit(x))val.push(""+x);
else val.push(val.pop()+val.pop()+x);
}
System.out.println(val.pop());
}
public static void postfixToPrefix (String str) {
Stack<String> val=new Stack<>();
for(char x:str.toCharArray()){
if(Character.isDigit(x))val.push(""+x);
else{
String val2=val.pop();
String val1=val.pop();
val.push(x+val1+val2);
}
}
System.out.println(val.pop());
}
public static void postfixToInfix (String str) {
Stack<String> val=new Stack<>();
for(char x:str.toCharArray()){
if(Character.isDigit(x))val.push(""+x);
else{
String val2=val.pop();
String val1=val.pop();
val.push(val1+x+val2);
}
}
System.out.println(val.pop());
}
public static void prefixToInfix (String str) {
Stack<String> val=new Stack<>();
for(int i=str.length()-1;i>=0;i--){
char x=str.charAt(i);
if(Character.isDigit(x))val.push(""+x);
else{
String val1=val.pop();
String val2=val.pop();
val.push(val1+x+val2);
}
}
System.out.println(val.pop());
}
public int celebrity(int mat[][]) {
//A celebrity is a person who is known to all but does not know anyone at a party
Stack<Integer> stk=new Stack<>();
for(int i=0;i<mat.length;i++)
stk.push(i);
while(stk.size()>1){
int v2=stk.pop();
int v1=stk.pop();
if(mat[v1][v2]==0)stk.push(v1);
else if(mat[v2][v1]==0)stk.push(v2);
}
if(stk.size()==0)return -1;
int ans=stk.pop();
for(int j=0;j<mat[0].length;j++){
if(mat[ans][j]==1)return -1;
}
for(int i=0;i<mat.length;i++){
if(i==ans)continue;
if(mat[i][ans]==0)return -1;
}
return ans;
}
public static void main(String[] args) {
//int arr[]={1,5,8,7,4,3,7};
//infix 9-5+3*4/6
//prefix -9/*+5346
//postfix 953+4*6/-
prefixToInfix("-9/*+5346");
}
}
class MyStack1{
public static int arr[];int indx=-1;
public MyStack1(int size){
arr=new int[size];
}
public void push(int element){
if(indx<arr.length){
arr[++indx]=element;
}else System.out.println("stack full");
}
public int capacity(){
return arr.length;
}
public int pop(){
if(indx>=0&&indx<arr.length)return arr[indx--];
else System.out.println("can't pop indx is out of stack");
return -1;
}
public void reverse(){
for(int i=indx;i>=0;i--)
System.out.print(arr[i]+" ");
}
public void insertAt(int indx,int element){
if(size()==arr.length){
System.out.println("stack overflow");
return;
}
if(size()==indx){
push(element);
return;
}
int x=pop();
insertAt(indx, element);
push(x);
}
public void deleteAt(int indx){
if(size()==0){
System.out.println("stack undeflow");
return;
}
if(size()==indx+1){
pop();
return;
}
int x=pop();
deleteAt(indx);
push(x);
}
public int peek(){
return arr[indx];
}
public int size(){
return indx+1;
}
public boolean isEmpty(){
return indx==-1;
}
public String toString(){
StringBuilder sb=new StringBuilder();
sb.append("[");
for(int i=0;i<=indx;i++){
sb.append(arr[i]+",");
}
sb.deleteCharAt(sb.length()-1);
sb.append("]");
return sb.toString();
}
}
class MyStack2 extends MyLinkedList{
Node t=new Node(100);
Node head=t.next;int size=0;
public void push(int x){
Node temp=new Node(x);
temp.next=head;
head=temp;
size++;
}
public int pop(){
int x=head.data;
head=head.next;
size--;
return x;
}
int size(){
return size;
}
boolean isEmpty(){
return size==0;
}
int peek(){
return head.data;
}
public String toString(){
StringBuilder sb=new StringBuilder();
MyStack1 m=new MyStack1(size);
for(Node temp=head;temp!=null;temp=temp.next){
m.push(temp.data);
} sb.append("[");
while(m.size()>0){
sb.append(m.pop()+",");
}
sb.deleteCharAt(sb.length()-1);
sb.append("]");
return sb.toString();
}
}