✨ [1572] Matrix Diagonal Sum

Author: enkr1

1572/my_solution.js

@@ -0,0 +1,34 @@
+/**
+ * @param {number[][]} mat
+ * @return {number}
+ */
+var diagonalSum = function (mat) {
+  let sum = 0, l = 0, r = mat[0].length - 1;
+
+  for (let row = 0; row < mat.length; row++) {
+    // for (let c = 0; c < mat[r].length; c++) {
+    console.log(`mat[row][l]:${mat[row][l]}, mat[row][r]:${mat[row][r]}`)
+    if (l === r) { // intersect
+      sum += mat[row][l];
+    } else {
+      sum += mat[row][l] + mat[row][r];
+    }
+
+    l++;
+    r--;
+    // }
+  }
+
+  return sum;
+};
+
+let x = null;
+x = diagonalSum([
+  [1, 2, 3],
+  [4, 5, 6],
+  [7, 8, 9]
+])
+
+
+console.log("Result");
+console.log(x);

1572/solution.js

@@ -0,0 +1,21 @@
+/**
+ * @param {number[][]} mat
+ * @return {number}
+ */
+var diagonalSum = function (mat) {
+  let sum = 0, l = 0, r = mat[0].length - 1;
+
+  for (let row = 0; row < mat.length; row++) {
+    if (l === r) {
+      sum += mat[row][l];
+    } else {
+      sum += mat[row][l] + mat[row][r];
+    }
+
+    l++;
+    r--;
+  }
+
+  return sum;
+};
+

README.md

@@ -74,6 +74,7 @@
 - [1365. How Many Numbers Are Smaller Than the Current Number](./1365/)
 - [1512. Number of Good Pairs](./1512/)
 - [1569. Number of Ways to Reorder Array to Get Same BST](./1569/)
+- [1572. Matrix Diagonal Sum](./1572/)
 - [1672. Richest Customer Wealth](./1672/)
 - [1791. Find Center of Star Graph](./1791/)
 - [1909. Remove One Element to Make the Array Strictly Increasing](./1909/)
@@ -106,7 +107,7 @@ iex ./.../solution.ex
 
 Batch create:
 ```ssh
-chapter=997 && mkdir ./$chapter && touch ./$chapter/my_solution.ex && touch ./$chapter/solution.ex && alias x="iex ./$chapter/my_solution.ex"
+chapter=1572 && mkdir ./$chapter && touch ./$chapter/my_solution.ex && touch ./$chapter/solution.ex && alias x="iex ./$chapter/my_solution.ex"
 ```
 > then you can use `x` for quick debug.
 
@@ -128,7 +129,7 @@ Batch create:
 NOTE: JS IS HERE
 -->
 ```ssh
-chapter=2448 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
+chapter=1572 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
 ```
 > then you can use `x` for quick debug.