day 38: 74-search-a-2d-matrix

74-search-a-2d-matrix/driver.cpp

@@ -0,0 +1,11 @@
+#include "soln.hpp"
+
+int main()
+{
+	vector<vector<int>> matrix = {{1, 3, 5, 7}, {10, 11, 16, 20}, {23, 30, 34, 60}};
+	int target = 3;
+	bool answer = true;
+	Solution soln;
+	cout << "Searched matrix correctly? " << soln.test(matrix, target, answer) << endl;
+	return 0;
+}

74-search-a-2d-matrix/soln.cpp

@@ -0,0 +1,62 @@
+#include "soln.hpp"
+
+bool Solution::searchMatrix(vector<vector<int>> &matrix, int target)
+{
+	int m = matrix.size(), n = matrix[0].size();
+	if (m == 1 && n == 1)
+	{
+		return matrix[0][0] == target;
+	}
+	int low = 0, high = m - 1;
+	int row_mid = (low + high) / 2, mid = -1;
+	if (m != 1)
+	{
+		while (low < high)
+		{
+			if (matrix[row_mid][0] == target)
+			{
+				return true;
+			}
+			else
+			{
+				if (matrix[row_mid][0] > target)
+				{
+					high = row_mid;
+				}
+				else if (matrix[row_mid][n - 1] < target)
+				{
+					low = row_mid + 1;
+				}
+				else
+				{
+					break;
+				}
+			}
+			row_mid = (low + high) / 2;
+		}
+	}
+	low = 0, high = n - 1;
+	mid = (low + high) / 2;
+	while (low < high)
+	{
+		if (matrix[row_mid][mid] == target)
+		{
+			return true;
+		}
+		else if (matrix[row_mid][mid] < target)
+		{
+			low = mid + 1;
+		}
+		else
+		{
+			high = mid;
+		}
+		mid = (low + high) / 2;
+	}
+	return matrix[row_mid][mid] == target;
+}
+
+bool Solution::test(vector<vector<int>> &matrix, int target, bool answer)
+{
+	return searchMatrix(matrix, target) == answer;
+}

74-search-a-2d-matrix/soln.hpp

@@ -0,0 +1,8 @@
+#include <bits/stdc++.h>
+using namespace std;
+class Solution
+{
+public:
+	bool searchMatrix(vector<vector<int>> &matrix, int target);
+	bool test(vector<vector<int>> &matrix, int target, bool answer);
+};