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Author: BaseMax

MergeSort.c

@@ -0,0 +1,72 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void merge(int arr[], int p, int q, int r) {
+    // Create L ← A[p..q] and M ← A[q+1..r]
+    int n1 = q - p + 1;
+    int n2 = r - q;
+
+    int L[n1], M[n2];
+
+    for (int i = 0; i < n1; i++) L[i] = arr[p + i];
+    for (int j = 0; j < n2; j++) M[j] = arr[q + 1 + j];
+
+    // Maintain current index of sub-arrays and main array
+    int i, j, k;
+    i = 0;
+    j = 0;
+    k = p;
+
+    // Until we reach either end of either L or M, pick larger among
+    // elements L and M and place them in the correct position at A[p..r]
+    while (i < n1 && j < n2) {
+        if (L[i] <= M[j]) {
+            arr[k] = L[i];
+            i++;
+        } else {
+            arr[k] = M[j];
+            j++;
+        }
+        k++;
+    }
+
+    // When we run out of elements in either L or M,
+    // pick up the remaining elements and put in A[p..r]
+    while (i < n1) {
+        arr[k] = L[i];
+        i++;
+        k++;
+    }
+
+    while (j < n2) {
+        arr[k] = M[j];
+        j++;
+        k++;
+    }
+}
+
+void merge_sort(int arr[], int l, int r) {
+    if (l < r) {
+        // m is the point where the array is divided into two subarrays
+        int m = l + (r - l) / 2;
+
+        merge_sort(arr, l, m);
+        merge_sort(arr, m + 1, r);
+
+        // Merge the sorted subarrays
+        merge(arr, l, m, r);
+    }
+}
+
+int main(int argc, char** argv) {
+    int arr[] = { 5, 4, 3, 2, 1 };
+    int n = sizeof(arr) / sizeof(arr[0]);
+
+    merge_sort(arr, 0, n - 1);
+
+    for (int i = 0; i < n; i++) {
+        printf("%d ", arr[i]);
+    }
+
+    return 0;
+}

binary_search.c

@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+// int binary_search(int* arr, int looking_for, int low, int high) {
+//     int middle = (int) (high + low) / 2;
+//     if (low == high && low == middle && arr[low] == looking_for) {
+//         return low;
+//     }
+//     return -1;
+// }
+
+int BinarySearch(int* arr, int looking_for, int low, int high) {
+    int middle = (int) (high + low) / 2;
+    if (low == high && low == middle && arr[low] == looking_for) {
+        return low;
+    }
+    if (arr[middle] == looking_for) {
+        return middle;
+    }
+    if (arr[middle] > looking_for) {
+        return BinarySearch(arr, looking_for, low, middle);
+    }
+    if (arr[middle] < looking_for) {
+        return BinarySearch(arr, looking_for, middle, high);
+    }
+    return -1;
+}
+
+int binarysearch_rec(int* arr, int low, int high, int looking_for) {
+    if (low <= high) {
+        int mid = (int) ceil( (low+high) / 2 );
+        if (looking_for == arr[mid]) return mid;
+        if (looking_for < arr[mid]) return binarysearch_rec(arr, low, mid-1, looking_for);
+        if (looking_for > arr[mid]) return binarysearch_rec(arr, mid+1, high, looking_for);
+    }
+    return -1;
+}
+
+int main () {
+
+    int arr[] = { 1, 3, 5, 9, 13, 17, 25 };
+    int n = sizeof(arr) / sizeof(arr[0]);
+    int looking_for = 17;
+    // int looking_for = 222;
+
+    // int found_key = BinarySearch(arr, looking_for, 0, n);
+    int found_key = binarysearch_rec(arr, looking_for, 0, n);
+    if (found_key == -1) {
+        printf("Error: sorry, we are unable to find that value in the array!\n");
+    } else {
+        printf("We found the %d value at arr[%d]\n");
+    }
+
+    return 0;
+}

binary_sort.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void binary_sort
+int main () {
+    return 0;
+}