Add KMP Search Algorithm

search/Knuth-Morris-Pratt (KMP) Algorithm for Pattern Searching

@@ -0,0 +1,57 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+vector<int> computeLPSArray(string& pattern) {
+    int m = pattern.size();
+    vector<int> lps(m);
+    int len = 0;
+    int i = 1;
+
+    while (i < m) {
+        if (pattern[i] == pattern[len]) {
+            len++;
+            lps[i] = len;
+            i++;
+        } else {
+            if (len != 0) {
+                len = lps[len - 1];
+            } else {
+                lps[i] = 0;
+                i++;
+            }
+        }
+    }
+    return lps;
+}
+
+void KMP(string& text, string& pattern) {
+    int n = text.size();
+    int m = pattern.size();
+    vector<int> lps = computeLPSArray(pattern);
+    int i = 0, j = 0;
+
+    while (i < n) {
+        if (pattern[j] == text[i]) {
+            i++;
+            j++;
+        }
+
+        if (j == m) {
+            cout << "Pattern found at index " << i - j << endl;
+            j = lps[j - 1];
+        } else if (i < n && pattern[j] != text[i]) {
+            if (j != 0) {
+                j = lps[j - 1];
+            } else {
+                i++;
+            }
+        }
+    }
+}
+
+int main() {
+    string text = "ababcabcabababd";
+    string pattern = "ababd";
+    KMP(text, pattern);
+    return 0;
+}

search/Quickselect for Finding the k-th Smallest Element.cpp

@@ -0,0 +1,37 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int partition(vector<int>& arr, int left, int right) {
+    int pivot = arr[right];
+    int i = left;
+
+    for (int j = left; j < right; ++j) {
+        if (arr[j] <= pivot) {
+            swap(arr[i], arr[j]);
+            i++;
+        }
+    }
+    swap(arr[i], arr[right]);
+    return i;
+}
+
+int quickSelect(vector<int>& arr, int left, int right, int k) {
+    if (left == right) return arr[left];
+
+    int pivotIndex = partition(arr, left, right);
+
+    if (k == pivotIndex) {
+        return arr[k];
+    } else if (k < pivotIndex) {
+        return quickSelect(arr, left, pivotIndex - 1, k);
+    } else {
+        return quickSelect(arr, pivotIndex + 1, right, k);
+    }
+}
+
+int main() {
+    vector<int> arr = {3, 2, 1, 5, 6, 4};
+    int k = 2;
+    cout << k << "-th smallest element is " << quickSelect(arr, 0, arr.size() - 1, k - 1) << endl;
+    return 0;
+}

search/Staircase Search in a 2D Matrix

@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+bool staircaseSearch(vector<vector<int>>& matrix, int target) {
+    int rows = matrix.size();
+    int cols = matrix[0].size();
+    int row = 0, col = cols - 1;
+
+    while (row < rows && col >= 0) {
+        if (matrix[row][col] == target) {
+            return true;
+        } else if (matrix[row][col] > target) {
+            col--;
+        } else {
+            row++;
+        }
+    }
+    return false;
+}
+
+int main() {
+    vector<vector<int>> matrix = {
+        {1, 4, 7, 11},
+        {2, 5, 8, 12},
+        {3, 6, 9, 16},
+        {10, 13, 14, 17}
+    };
+    int target = 8;
+    if (staircaseSearch(matrix, target))
+        cout << "Element found." << endl;
+    else
+        cout << "Element not found." << endl;
+
+    return 0;
+}