Merge pull request #210 from nhistory/Week14

[Sehwan] Week14 solution with JavaScript

Author: nhistory

set-matrix-zeroes/nhistory.js

@@ -0,0 +1,24 @@
+var setZeroes = function (matrix) {
+  let rows = new Set();
+  let cols = new Set();
+
+  for (let row = 0; row < matrix.length; row++) {
+    for (let col = 0; col < matrix[0].length; col++) {
+      if (matrix[row][col] === 0) {
+        rows.add(row);
+        cols.add(col);
+      }
+    }
+  }
+
+  for (let row = 0; row < matrix.length; row++) {
+    for (let col = 0; col < matrix[0].length; col++) {
+      if (rows.has(row) || cols.has(col)) {
+        matrix[row][col] = 0;
+      }
+    }
+  }
+};
+
+// TC: O(m*n)
+// SC: O(m+n)

spiral-matrix/nhistory.js

@@ -0,0 +1,45 @@
+var spiralOrder = function (matrix) {
+  // Edge case
+  if (matrix.length === 0) return [];
+
+  let result = [];
+  let rowStart = 0,
+    rowEnd = matrix.length - 1;
+  let colStart = 0,
+    colEnd = matrix[0].length - 1;
+
+  while (rowStart <= rowEnd && colStart <= colEnd) {
+    // Traverse right
+    for (let col = colStart; col <= colEnd; col++) {
+      result.push(matrix[rowStart][col]);
+    }
+    rowStart++;
+
+    // Traverse down
+    for (let row = rowStart; row <= rowEnd; row++) {
+      result.push(matrix[row][colEnd]);
+    }
+    colEnd--;
+
+    // Traverse left (check if rowStart <= rowEnd to avoid duplicates)
+    if (rowStart <= rowEnd) {
+      for (let col = colEnd; col >= colStart; col--) {
+        result.push(matrix[rowEnd][col]);
+      }
+      rowEnd--;
+    }
+
+    // Traverse up (check if colStart <= colEnd to avoid duplicates)
+    if (colStart <= colEnd) {
+      for (let row = rowEnd; row >= rowStart; row--) {
+        result.push(matrix[row][colStart]);
+      }
+      colStart++;
+    }
+  }
+
+  return result;
+};
+
+// TC: O(m*n)
+// SC: O(m*n)

sum-of-two-integers/nhistory.js

@@ -0,0 +1,16 @@
+var getSum = function (a, b) {
+  while (b !== 0) {
+    if (b > 0) {
+      a++;
+      b--;
+    } else {
+      b++;
+      a--;
+    }
+  }
+  return a;
+};
+
+// |b| is absolute value of b
+// TC: O(|b|)
+// SC: O(1)