Add solution #1253

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,197 LeetCode solutions in JavaScript
+# 1,198 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -955,6 +955,7 @@
 1249|[Minimum Remove to Make Valid Parentheses](./solutions/1249-minimum-remove-to-make-valid-parentheses.js)|Medium|
 1250|[Check If It Is a Good Array](./solutions/1250-check-if-it-is-a-good-array.js)|Hard|
 1252|[Cells with Odd Values in a Matrix](./solutions/1252-cells-with-odd-values-in-a-matrix.js)|Easy|
+1253|[Reconstruct a 2-Row Binary Matrix](./solutions/1253-reconstruct-a-2-row-binary-matrix.js)|Medium|
 1261|[Find Elements in a Contaminated Binary Tree](./solutions/1261-find-elements-in-a-contaminated-binary-tree.js)|Medium|
 1267|[Count Servers that Communicate](./solutions/1267-count-servers-that-communicate.js)|Medium|
 1268|[Search Suggestions System](./solutions/1268-search-suggestions-system.js)|Medium|

solutions/1253-reconstruct-a-2-row-binary-matrix.js

@@ -0,0 +1,62 @@
+/**
+ * 1253. Reconstruct a 2-Row Binary Matrix
+ * https://leetcode.com/problems/reconstruct-a-2-row-binary-matrix/
+ * Difficulty: Medium
+ *
+ * Given the following details of a matrix with n columns and 2 rows:
+ * - The matrix is a binary matrix, which means each element in the matrix can be 0 or 1.
+ * - The sum of elements of the 0-th(upper) row is given as upper.
+ * - The sum of elements of the 1-st(lower) row is given as lower.
+ * - The sum of elements in the i-th column(0-indexed) is colsum[i], where colsum is given as an
+ *   integer array with length n.
+ *
+ * Your task is to reconstruct the matrix with upper, lower and colsum.
+ * Return it as a 2-D integer array.
+ * If there are more than one valid solution, any of them will be accepted.
+ * If no valid solution exists, return an empty 2-D array.
+ */
+
+/**
+ * @param {number} upper
+ * @param {number} lower
+ * @param {number[]} colsum
+ * @return {number[][]}
+ */
+var reconstructMatrix = function(upper, lower, colsum) {
+  const n = colsum.length;
+  const matrix = [[], []];
+  let upperLeft = upper;
+  let lowerLeft = lower;
+
+  for (let i = 0; i < n; i++) {
+    if (colsum[i] === 2) {
+      matrix[0][i] = 1;
+      matrix[1][i] = 1;
+      upperLeft--;
+      lowerLeft--;
+    } else {
+      matrix[0][i] = 0;
+      matrix[1][i] = 0;
+    }
+  }
+
+  if (upperLeft < 0 || lowerLeft < 0) return [];
+
+  for (let i = 0; i < n; i++) {
+    if (colsum[i] === 1) {
+      if (upperLeft > 0) {
+        matrix[0][i] = 1;
+        matrix[1][i] = 0;
+        upperLeft--;
+      } else if (lowerLeft > 0) {
+        matrix[0][i] = 0;
+        matrix[1][i] = 1;
+        lowerLeft--;
+      } else {
+        return [];
+      }
+    }
+  }
+
+  return upperLeft === 0 && lowerLeft === 0 ? matrix : [];
+};