Diagonal Traverse

Author: lessfish

Algorithms/Diagonal Traverse/diagonal-traverse.js

@@ -0,0 +1,62 @@
+// Source : https://leetcode.com/problems/diagonal-traverse/
+// Author : Han Zichi
+// Date   : 2017-02-07
+
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var findDiagonalOrder = function(matrix) {
+  let M = matrix.length;
+  if (!M) return [];
+  let N = matrix[0].length;
+
+  let res = [];
+
+  // first row
+  for (let i = 0; i < N; i++) {
+    let x = 0
+      , y = i
+      , tmp = [];
+
+    while (true) {
+      tmp.push(matrix[x][y]);
+      x++;
+      y--;
+
+      if (x < 0 || x >= M || y < 0 || y >= N)
+        break;
+    }
+
+    res.push(tmp);
+  }
+
+  // last column
+  for (let i = 1; i < M; i++) {
+    let x = i
+      , y = N - 1
+      , tmp = [];
+
+    while (true) {
+      tmp.push(matrix[x][y]);
+      x++;
+      y--;
+
+      if (x < 0 || x >= M || y < 0 || y >= N)
+        break;
+    }
+
+    res.push(tmp);
+  }
+
+  let ans = [];
+  res.forEach(function(item, index) {
+    if (!(index & 1)) {
+      ans.push(...item.reverse());
+    } else {
+      ans.push(...item);
+    }
+  });
+
+  return ans;
+};