add leetcode 73

73.set_matrix_zeroes/main.go

@@ -0,0 +1,118 @@
+package main
+
+// additional memory approach
+// time complexity: O(M * N) where M and N are the number
+// of the rows and columns
+//
+// space complexity: O(M + N)
+func setZeroes(matrix [][]int) {
+	rows := make(map[int]bool)
+	cols := make(map[int]bool)
+	for i := 0; i < len(matrix); i++ {
+		for j := 0; j < len(matrix[0]); j++ {
+			if matrix[i][j] == 0 {
+				rows[i], cols[j] = true, true
+			}
+		}
+	}
+
+	for i := 0; i < len(matrix); i++ {
+		for j := 0; j < len(matrix[0]); j++ {
+			if rows[i] || cols[j] {
+				matrix[i][j] = 0
+			}
+		}
+	}
+}
+
+// use the matrix itself as the indicators
+// time complexity: O(M * N)
+// space complexity: O(1)
+//
+// the ideas is that we can use the first cell of every row
+// and column as a flag. this flag would determine whether
+// a row or column has been set to zero.
+func setZeroes2(matrix [][]int) {
+	rows, cols := len(matrix), len(matrix[0])
+	zeroRow, zeroCol := false, false
+	for row := 0; row < rows; row++ {
+		for col := 0; col < cols; col++ {
+			if matrix[row][col] == 0 {
+				if row == 0 {
+					zeroRow = true
+				} else {
+					matrix[row][0] = 0
+				}
+
+				if col == 0 {
+					zeroCol = true
+				} else {
+					matrix[0][col] = 0
+				}
+			}
+		}
+	}
+
+	for row := 1; row < rows; row++ {
+		for col := 1; col < cols; col++ {
+			if matrix[row][0] == 0 || matrix[0][col] == 0 {
+				matrix[row][col] = 0
+			}
+		}
+	}
+
+	if zeroRow {
+		for col := 0; col < cols; col++ {
+			matrix[0][col] = 0
+		}
+	}
+
+	if zeroCol {
+		for row := 0; row < rows; row++ {
+			matrix[row][0] = 0
+		}
+	}
+}
+
+// same ideas as setZeroes2
+// time complexity: O(M * N)
+// space complexity: O(1)
+func setZeroes3(matrix [][]int) {
+	rows, cols := len(matrix), len(matrix[0])
+	zeroCol := false
+	for row := 0; row < rows; row++ {
+		if matrix[row][0] == 0 {
+			zeroCol = true
+		}
+
+		for col := 1; col < cols; col++ {
+			// as a flag
+			if matrix[row][col] == 0 {
+				matrix[0][col] = 0
+				// wether which element is zero in row[0], matrix[0][0] will be setting to zero
+				// so if matrix[0][0] is zero that mean all of element in the first row must be to set zero
+				matrix[row][0] = 0
+			}
+		}
+	}
+
+	for row := 1; row < rows; row++ {
+		for col := 1; col < cols; col++ {
+			if matrix[0][col] == 0 || matrix[row][0] == 0 {
+				matrix[row][col] = 0
+			}
+		}
+	}
+
+	if matrix[0][0] == 0 {
+		for col := 1; col < cols; col++ {
+			matrix[0][col] = 0
+		}
+	}
+
+	if zeroCol {
+		for row := 0; row < rows; row++ {
+			matrix[row][0] = 0
+		}
+	}
+}

73.set_matrix_zeroes/main_test.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestSetZeroes(t *testing.T) {
+	for _, tt := range []struct {
+		matrix [][]int
+		want   [][]int
+	}{{
+		matrix: [][]int{{1, 1, 1}, {1, 0, 1}, {1, 1, 1}},
+		want:   [][]int{{1, 0, 1}, {0, 0, 0}, {1, 0, 1}},
+	}, {
+		matrix: [][]int{{0, 1, 2, 0}, {3, 4, 5, 2}, {1, 3, 1, 5}},
+		want:   [][]int{{0, 0, 0, 0}, {0, 4, 5, 0}, {0, 3, 1, 0}},
+	}} {
+		matrix1 := shallowCopy2DSlice(tt.matrix)
+		setZeroes(matrix1)
+		for i := 0; i < len(matrix1); i++ {
+			if !equal(tt.want[i], matrix1[i]) {
+				t.Errorf("got: %v, want: %v", matrix1[i], tt.want[i])
+			}
+		}
+
+		matrix2 := shallowCopy2DSlice(tt.matrix)
+		setZeroes2(matrix2)
+		for i := 0; i < len(matrix2); i++ {
+			if !equal(tt.want[i], matrix2[i]) {
+				t.Errorf("got: %v, want: %v", matrix2[i], tt.want[i])
+			}
+		}
+
+		matrix3 := shallowCopy2DSlice(tt.matrix)
+		setZeroes3(matrix3)
+		for i := 0; i < len(matrix3); i++ {
+			if !equal(tt.want[i], matrix3[i]) {
+				t.Errorf("got: %v, want: %v", matrix3[i], tt.want[i])
+			}
+		}
+	}
+}
+
+func shallowCopy2DSlice(matrix [][]int) [][]int {
+	shallow := make([][]int, len(matrix))
+	for i := range matrix {
+		arr := make([]int, len(matrix[0]))
+		copy(arr, matrix[i])
+		shallow[i] = arr
+	}
+	return shallow
+}
+
+func equal(expect, actual []int) bool {
+	if len(expect) != len(actual) {
+		return false
+	}
+
+	for i := 0; i < len(expect); i++ {
+		if expect[i] != actual[i] {
+			return false
+		}
+	}
+	return true
+}

README.md

@@ -32,7 +32,8 @@
 |66|[Plus One](https://leetcode.com/problems/plus-one)|$\color{green}{\textsf{Easy}}$||
 |67|[Add Binary](https://leetcode.com/problems/add-binary)|$\color{green}{\textsf{Easy}}$||
 |69|[Sqrt(x)](https://leetcode.com/problems/sqrtx)|$\color{green}{\textsf{Easy}}$||
-|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs)|$\color{green}{\textsf{Easy}}$||
+|70|[Climbing Stairs](https://leetcode.com/problems/climbing-stairs)|$\color{green}{\textsf{Easy}}$||  
+|73|[Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes)|$\color{orange}{\textsf{Medium}}$|[Go](https://github.com/xxxVitoxxx/leetcode/blob/main/73.set_matrix_zeroes/main.go)|  
 |75|[Sort Colors](https://leetcode.com/problems/sort-colors)|$\color{orange}{\textsf{Medium}}$|[Go](https://github.com/xxxVitoxxx/leetcode/blob/main/75.sort_colors/main.go)|
 |83|[Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list)|$\color{green}{\textsf{Easy}}$||
 |88|[Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array)|$\color{green}{\textsf{Easy}}$|[Go](https://github.com/xxxVitoxxx/leetcode/blob/main/88.merge_sorted_array/main.go)|