maximal rectangle

maxmimal.js

@@ -0,0 +1,51 @@
+/**
+ * @param {character[][]} matrix
+ * @return {number}
+ */
+var maximalRectangle = function largestRectangle(matrix) {
+    if (matrix.length === 0 || matrix[0].length === 0) {
+      return 0;
+    }
+
+    const heights = Array(matrix[0].length).fill(0);
+    let maxArea = 0;
+
+    for (let row = 0; row < matrix.length; row++) {
+      for (let col = 0; col < matrix[0].length; col++) {
+        if (matrix[row][col] === 1) {
+          heights[col]++;
+        } else {
+          heights[col] = 0;
+        }
+      }
+
+      maxArea = Math.max(maxArea, largestRectangleArea(heights));
+    }
+
+    return maxArea;
+  }
+
+  function largestRectangleArea(heights) {
+    const stack = [-1];
+    let maxArea = 0;
+
+    for (let i = 0; i < heights.length; i++) {
+      while (stack.length > 1 && heights[stack[stack.length - 1]] >= heights[i]) {
+        maxArea = Math.max(
+          maxArea,
+          heights[stack.pop()] * (i - stack[stack.length - 1] - 1)
+        );
+      }
+      stack.push(i);
+    }
+
+    while (stack.length > 1) {
+      maxArea = Math.max(
+        maxArea,
+        heights[stack.pop()] * (heights.length - stack[stack.length - 1] - 1)
+      );
+    }
+
+    return maxArea;
+  };
+