Tricks and some other pattern added

Author: Vinay Patel

Pattern/Patterns.java

@@ -1,3 +1,20 @@
+// Never Asked by product based company like ( MAANG ) .
+// Sometimes Asked by service based company.
+
+// Patterns ----> (Nested Loops)
+
+// Trick to solve any pattern question
+
+// 1) for the outer loop , count the number of lines.
+
+// 2) for the inner loop , focus on the colums & connent them somehow to the rows. 
+
+// 3) print "*" inside the inner for loop.
+
+// 4) Observe symmetry [ Optimal ]
+
+
+
 class Patterns {
  public static void main(String[] args) {
  // pattern1(5);;
@@ -13,7 +30,15 @@ public static void main(String[] args) {
  // pattern11(5);
  // pattern12(5);
  // pattern13(5);
- pattern14(5);
+ // pattern14(5);
+ // pattern15(5);
+ // pattern16(5);
+ // pattern17(5);
+ // pattern18(5);
+ // pattern19(5);
+ // pattern20(5);
+ // pattern21(5);
+ // pattern22(4);
 
  }
 
@@ -279,5 +304,213 @@ public static void pattern14(int n){
  }
 
  }
+ public static void pattern15(int n){
+
+ // ABCDE
+ // ABCD 
+ // ABC 
+ // AB 
+ // A 
+
+ for (int i = 0; i < n; i++) {
+ for (char ch = 'A'; ch <= 'A'+(n-i-1); ch++) {
+ System.out.print(ch);
+ }
+ System.out.println();
+ }
+
+ }
+ 
+ public static void pattern16(int n){
+
+ // A
+ // BB
+ // CCC
+ // DDDD
+ // EEEEE
+
+ for (int i = 0; i < n; i++) {
+ char ch = (char) ('A' + i);
+ for (int j = 0; j <= i; j++) {
+ System.out.print(ch);
+ }
+ System.out.println();
+ }
+
+ }
+ 
+ public static void pattern17(int n){
+
+ // A 
+ // ABA
+ // ABCBA
+ // ABCDCBA
+ // ABCDEDCBA
+
+ for (int i = 0; i < n; i++) {
+ // space
+ for(int j=0;j<n-i-1;j++){
+ System.out.print(" ");
+ }
+ // star
+ char ch = 'A';
+ int breakpoint = (2*i+1)/2;
+ for(int j=1;j<=2*i + 1;j++){
+ System.out.print(ch);
+ // ch++;
+ if(j<=breakpoint)ch++;
+ else ch--;
+ }
+ // space
+ for(int j=0;j<n-i-1;j++){
+ System.out.print(" ");
+ }
+ System.out.println();
+ }
+
+ }
+ 
+ public static void pattern18(int n){
+
+ // E
+ // DE
+ // CDE
+ // BCDE
+ // ABCDE
+
+ for (int i = 0; i < n; i++) {
+ for(char ch=(char) ('E'-i);ch<='E';ch++){
+ System.out.print(ch);
+ }
+ System.out.println();
+ }
+
+ }
+ 
+ public static void pattern19(int n){
+
+ // **********
+ // **** ****
+ // *** ***
+ // ** **
+ // * *
+ // * *
+ // ** **
+ // *** ***
+ // **** ****
+ // **********
+
+ int iniSpace=0;
+ for (int i = 0; i < n; i++) {
+ // star
+ for(int j=1;j<=n-i;j++){
+ System.out.print("*");
+ }
+ // space
+ for(int j=0;j<iniSpace;j++){
+ System.out.print(" ");
+ }
+ // star
+ for(int j=1;j<=n-i;j++){
+ System.out.print("*");
+ }
+ iniSpace += 2;
+ System.out.println();
+ }
+
+
+ iniSpace=2*n -2;
+ for(int i=1;i<=n;i++){
+ // star
+ for(int j=1;j<=i;j++){
+ System.out.print("*");
+ }
+ // space
+ for(int j=0;j<iniSpace;j++){
+ System.out.print(" ");
+ }
+ // star
+ for(int j=1;j<=i;j++){
+ System.out.print("*");
+ }
+ iniSpace -= 2;
+ System.out.println();
+ 
+ }
+ }
+
+ public static void pattern22(int n) {
+
+ // 4444444
+ // 4333334
+ // 4322234
+ // 4321234
+ // 4322234
+ // 4333334
+ // 4444444
+
+ for (int i = 0; i < 2*n-1; i++) {
+ for (int j = 0; j < 2*n-1; j++) {
+ int top=i;
+ int left = j;
+ int right = (2*n- 2) -j;
+ int down = (2*n -2) - i;
+ System.out.print(n-Math.min(Math.min(top, down),Math.min(left, right)));
+ }
+ System.out.println();
+ }
+ }
+
+public static void pattern21(int n) {
+
+ // *****
+ // * *
+ // * *
+ // * *
+ // *****
+
+ for(int i=0;i<n;i++){
+ for(int j=0;j<n;j++){
+ if(i==0 || j == 0|| i== n-1 || j==n-1){
+ System.out.print("*");
+ }
+ else System.out.print(" ");
+ }
+ System.out.println();
+ }
+
+ }
+
+public static void pattern20(int n) {
+
+ // * *
+ // ** **
+ // *** ***
+ // **** ****
+ // **********
+ // **** ****
+ // *** ***
+ // ** **
+ // * *
+
+
+ int spaces = 2*n - 2;
+ for (int i = 1; i <=2*n-1; i++) {
+ int star = i;
+ if(i>n) star = 2*n -i;
+ for (int j = 1; j <= star; j++) {
+ System.out.print("*");
+ }
+ for(int j=1;j<=spaces;j++){
+ System.out.print(" ");
+ }
+ for (int j = 1; j <= star; j++) {
+ System.out.print("*");
+ }
+ System.out.println();
+ if(i<n) spaces -= 2;
+ else spaces +=2;
+ }
+ }
 
 }