Array

Duration 9 day
It is taking an extended amount of time because this repository has become a secondary priority. Our primary focus is currently on the JavaScript repository.

Author: SaurabhKumarDev

Array/Creation.java

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+import java.util.Arrays;
+
+public class Creation {
+    public static void main(String[] args) {
+        int arrInt[] = new int[2];
+        String arrString[] = new String[4];
+        char[] ch = {'a','b','c'};
+
+        // Inserting value's
+        arrInt[0] = 2;
+        arrInt[1] = 2;
+
+        arrString[0] = "4";
+        arrString[3] = "Four";
+        arrString[2] = "two";
+
+        ch[2] = 'd';
+
+        // Output
+        System.out.println(Arrays.toString(arrString));
+        System.out.println(Arrays.toString(arrInt));
+        System.out.println(Arrays.toString(ch));
+    }
+}

Array/binarySearch.java

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+public class binarySearch {
+    public static int binarySearch(int[] arr, int key) {
+        int beg = 0;
+        int end = arr.length;
+        for (int i=0; i<=arr.length; i++) {
+            int temp = end + beg;
+            if (arr[temp/2] == key) {
+                return (temp/2)+1;
+            } else if (arr[temp/2] > key) {
+                end = temp/2;
+            } else if (arr[temp/2] < key) {
+                beg = temp/2;
+            }
+        }
+        return -1;
+    }
+    public static void main(String[] args) {
+        int[] arr = {2,4,6,8,9};
+
+        System.out.print(binarySearch(arr, 4));
+    }
+}

Array/inFunction.java

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+public class inFunction {
+    public static void update(int[] arr) {
+        for (int i=0; i<arr.length; i++) { arr[i] += 1; System.out.println(arr[i]); }
+    }
+    public static void main(String[] args) {
+        int arr[] = {2,5,2,7};
+
+        // Call by reference
+        update(arr);
+
+        // Value is updated here for array
+    }
+}

Array/kadaneMaxSubArray.java

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+// 03) Kadane-s algorithm
+// Best aproch
+// +ve + +ve = +ve      Y
+// +ve + -ve = +ve      Y
+// +ve + ---ve = -ve    X
+// Time Complexity = O(N)
+
+public class kadaneMaxSubArray {
+    public static void main(String[] args) {
+        int arr[] = {1, -2, 6, -1, 3};
+        int currentSum = 0, maxSum = Integer.MIN_VALUE;
+
+        for (int i=0; i<arr.length; i++) {
+            currentSum += arr[i];
+            if (currentSum < 0) currentSum = 0;
+            maxSum = Math.max(maxSum, currentSum);
+        }
+        System.out.print(maxSum);
+    }
+}

Array/largest.java

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+import java.util.Arrays;
+
+public class largest {
+    public static int largest(int[] arr) {
+        int largest = Integer.MIN_VALUE;
+        for (int i=0; i<arr.length; i++) {
+            if (largest < arr[i]) {
+                largest = arr[i];
+            }
+        }
+        return largest;
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {4, 3, 5, -2, -6, -3, -9};
+        System.out.print(largest(arr)+"\n");
+
+        // Using inbuilt methods
+        System.out.println(Arrays.stream(arr).max());
+    }
+}

Array/linearSearch.java

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+public class linearSearch {
+    public static int linearSearch(int[] arr, int find) {
+        for (int i=0; i<arr.length; i++) {
+            if (arr[i] == find) { return i+1; }
+        }
+        return -1;
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {1,2,3,4,5,6,7,8,9,0};
+        int find = 10;
+        System.out.print(linearSearch(arr, find));
+    }
+}

Array/maxSubArray.java

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+// Max Sub Array
+// Applied Brute Force
+// TC - O(N^3)
+
+public class maxSubArray {
+    public static void maxSub(int arr[]) {
+        int maxSum = 0;
+       for (int k=0; k<arr.length; k++) {
+           int temp = arr[k];
+           for (int i=k; i<arr.length; i++) {
+               int tem = 0;
+               for (int j=k; j<=i; j++) {
+                   tem += arr[j];
+               }
+               if (tem >= temp) {
+                   temp = tem;
+               }
+           }
+           if (maxSum <= temp) {
+               maxSum = temp;
+           }
+           System.out.println(temp);
+       }
+       System.out.println("Max Sum : "+maxSum);
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {1, -2, 6, -1, 3};
+        maxSub(arr);
+    }
+}

Array/pairArray.java

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+public class pairArray {
+    public static void main(String[] args) {
+        int[] arr = {1,2,3,4,5,6,7,8,9};
+
+        for (int i=0; i<arr.length; i++) {
+            for (int j=i+1; j<arr.length; j++) {
+                System.out.print("("+arr[i]+","+arr[j]+") ");
+            }
+            System.out.println();
+        }
+    }
+}

Array/prefixMaxSubArray.java

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+// 02) Find the Max Sub Array
+// Time complexity = O(N^2)
+
+public class prefixMaxSubArray {
+    public static void main(String[] args) {
+        int arr[] = {1, -2, 6, -1, 3};
+        int maxValue = Integer.MIN_VALUE;
+
+        // Calculation within array
+        for (int j=0; j<arr.length; j++) {
+            int prefix[] = new int[arr.length];
+
+            for (int i=j; i<arr.length; i++) {
+                if (i != 0) {
+                    prefix[i] = arr[i] + prefix[i - 1];
+                    if (maxValue < prefix[i]) maxValue = prefix[i];
+                } else {
+                    maxValue = arr[i];
+                    prefix[i] = arr[i];
+                }
+            }
+        }
+        System.out.println("Max : "+maxValue);
+    }
+}

Array/reverseArray.java

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+public class reverseArray {
+    public static void main(String[] args) {
+        int[] arr = {1,2,3,4,5,6,7,8,9};
+
+        for (int i=0; i<arr.length/2; i++) {
+            int end = arr.length-i-1;
+
+            // Swap
+            int temp = arr[i];
+            arr[i] = arr[end];
+            arr[end] = temp;
+        }
+        for (int i=0; i<arr.length; i++) System.out.print(arr[i]+" ");
+    }
+}