Search a 2D matrix

searchA2DMatrix.js

@@ -0,0 +1,36 @@
+/**
+ * @param {number[][]} matrix
+ * @param {number} target
+ * @return {boolean}
+ * 
+ * Intution:
+ * Here we are imagining a 2d matrix as an array and performing the binary search
+ * I set the left to the first index and set the right to the last index 
+ * Inside the while loop,  we are deriving the row col based on two formulas, and performing the binary search.
+ */
+var searchMatrix = function(matrix, target) {
+    // Set left to the first element of the array
+    let left = 0; 
+    const totalCols = matrix[0].length;
+    // Set right to the last element of the array
+    let right = (matrix.length * matrix[0].length) - 1;
+
+    while(left <= right) {
+        const mid = Math.floor(left + (right-left)/2);
+        // formula to find the row number
+        const row = Math.floor(mid / totalCols);
+        // formula to find the col number
+        const col = Math.floor(mid % totalCols);
+        const currVal = matrix[row][col];
+        if(currVal === target) {
+            // return true if element is found
+            return true;
+        }else if(currVal < target) {
+            left = mid + 1;
+        }else {
+            right = mid - 1;
+        }
+    }
+    // return false if nothing is found
+    return false;
+};