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-rw-r--r--find_pos_int_soln_given_eq.c59
-rw-r--r--find_pos_int_soln_given_eq.py42
-rw-r--r--keyboard_row.c50
-rw-r--r--keyboard_row.py32
-rw-r--r--sudoku_solver.c69
-rw-r--r--sudoku_solver.py66
-rw-r--r--valid_sudoku.c55
-rw-r--r--valid_sudoku.py59
8 files changed, 432 insertions, 0 deletions
diff --git a/find_pos_int_soln_given_eq.c b/find_pos_int_soln_given_eq.c
new file mode 100644
index 0000000..b17ecf6
--- /dev/null
+++ b/find_pos_int_soln_given_eq.c
@@ -0,0 +1,59 @@
+// 1237. Find Positive Integer Solution for a Given Equation
+#include "leetcode.h"
+
+/*
+ * given a callable function 'f(x, y)' with a hidden formula and a value 'z',
+ * reverse engineer the formula and return all positive integer pairs 'x' and
+ * 'y' where 'f(x, y) == z'. you may return the pairs in any order. while the
+ * exact formula is hidden, the function is monotonically increasing.
+ */
+
+int function_id = 0;
+
+int customFunction(int x, int y) {
+ switch (function_id) {
+ case 1:
+ return x + y;
+ case 2:
+ return x * y;
+ }
+}
+
+int **findSolution(int (*customFunction)(int, int), int z, int *returnSize,
+ int **returnColumnSizes) {
+ int **ans = (int **)malloc(z * sizeof(int *)), k = 0;
+ int *cols = *returnColumnSizes = (int *)malloc(z * sizeof(int));
+ for (int i = 1; i <= z; i++)
+ for (int j = z; j >= 1; j--)
+ if (customFunction(i, j) == z) {
+ (ans[k] = (int *)malloc(sizeof(int[cols[k] = 2])))[0] = i;
+ ans[k++][1] = j;
+ }
+ *returnSize = k;
+ return ans;
+}
+
+int main() {
+ function_id = 1;
+ int rs1, *rcs1, **fs1 = findSolution(customFunction, 5, &rs1, &rcs1);
+ for (int i = 0; i < rs1; i++) {
+ for (int j = 0; j < rcs1[i]; j++)
+ printf("%d ", fs1[i][j]); // expect: [[1,4],[2,3],[3,2],[4,1]]
+ printf("\n");
+ }
+ function_id = 2;
+ int rs2, *rcs2, **fs2 = findSolution(customFunction, 5, &rs2, &rcs2);
+ for (int i = 0; i < rs2; i++) {
+ for (int j = 0; j < rcs2[i]; j++)
+ printf("%d ", fs2[i][j]); // expect: [[1,5],[5,1]]
+ printf("\n");
+ }
+ for (int i = 0; i < rs1; i++)
+ free(fs1[i]);
+ free(rcs1);
+ free(fs1);
+ for (int i = 0; i < rs2; i++)
+ free(fs2[i]);
+ free(rcs2);
+ free(fs2);
+}
diff --git a/find_pos_int_soln_given_eq.py b/find_pos_int_soln_given_eq.py
new file mode 100644
index 0000000..5474513
--- /dev/null
+++ b/find_pos_int_soln_given_eq.py
@@ -0,0 +1,42 @@
+# 1237. Find Positive Integer Solution for a Given Equation
+
+"""
+given a callable function 'f(x, y)' with a hidden formula and a value 'z',
+reverse engineer the formula and return all positive integer pairs 'x' and
+'y' where 'f(x, y) == z'. you may return the pairs in any order. while the
+exact formula is hidden, the function is monotonically increasing.
+"""
+
+function_id = 0
+
+
+class customfunction(object):
+ def f(self, x, y):
+ if function_id == 1:
+ return x + y
+ if function_id == 2:
+ return x * y
+
+
+class Solution(object):
+ def findSolution(self, customfunction, z):
+ """
+ :type num: int
+ :type z: int
+ :rtype: List[List[int]]
+ """
+ ans, y = [], 1000
+ for x in range(1, 1001):
+ while y > 1 and customfunction.f(x, y) > z:
+ y -= 1
+ if customfunction.f(x, y) == z:
+ ans.append([x, y])
+ return ans
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ function_id = 1
+ print(obj.findSolution(customfunction, 5))
+ function_id = 2
+ print(obj.findSolution(customfunction, 5))
diff --git a/keyboard_row.c b/keyboard_row.c
new file mode 100644
index 0000000..b01224e
--- /dev/null
+++ b/keyboard_row.c
@@ -0,0 +1,50 @@
+// 500. Keyboard Row
+#include "leetcode.h"
+
+/*
+ * given an array of strings 'words', return the words that can be typed using
+ * letters of the alphabet on only one row of american keyboard like the image
+ * below. note that the strings are case insensitive, both lowercased and
+ * uppercased of the same letter are treated as if they are at the same row.
+ */
+
+char **findWords(char **words, int wordsSize, int *returnSize) {
+ char **ans = (char **)malloc(wordsSize * sizeof(char *));
+ int idx = 0, lut[26] = {2, 3, 3, 2, 1, 2, 2, 2, 1, 2, 2, 2, 3,
+ 3, 1, 1, 1, 1, 2, 1, 1, 3, 1, 3, 1, 3};
+ bool same_line = true;
+ for (int i = 0; i < wordsSize; i++) {
+ same_line = true;
+ for (int j = 0; j < strlen(words[i]); j++) {
+ if (lut[(words[i][j] - 'A') % 32] != lut[(words[i][j + 1] - 'A') % 32]) {
+ same_line = false;
+ break;
+ }
+ }
+ if (same_line)
+ ans[idx++] = words[i];
+ }
+ *returnSize = idx;
+ return ans;
+}
+
+int main() {
+ char *w1[] = {"Hello", "Alaska", "Dad", "Peace"}, *w2[] = {"omk"},
+ *w3[] = {"adsdf", "sfd"};
+ int rs1, rs2, rs3;
+ char **fw1 = findWords((char **)w1, ARRAY_SIZE(w1), &rs1);
+ char **fw2 = findWords((char **)w2, ARRAY_SIZE(w2), &rs2);
+ char **fw3 = findWords((char **)w3, ARRAY_SIZE(w3), &rs3);
+ for (int i = 0; i < rs1; i++)
+ printf("%s ", fw1[i]); // expect: Alaska Dad
+ printf("\n");
+ for (int i = 0; i < rs2; i++)
+ printf("%s ", fw2[i]); // expect: omk
+ printf("\n");
+ for (int i = 0; i < rs3; i++)
+ printf("%s ", fw3[i]); // expect: adsdf sfd
+ printf("\n");
+ free(fw1);
+ free(fw2);
+ free(fw3);
+}
diff --git a/keyboard_row.py b/keyboard_row.py
new file mode 100644
index 0000000..e4e92d8
--- /dev/null
+++ b/keyboard_row.py
@@ -0,0 +1,32 @@
+# 500. Keyboard Row
+
+"""
+given an array of strings 'words', return the words that can be typed using
+letters of the alphabet on only one row of american keyboard like the image
+below. note that the strings are case insensitive, both lowercased and
+uppercased of the same letter are treated as if they are at the same row.
+"""
+
+
+class Solution(object):
+ def findWords(self, words):
+ """
+ :type words: List[str]
+ :rtype: List[str]
+ """
+ l1 = set("qwertyuiop")
+ l2 = set("asdfghjkl")
+ l3 = set("zxcvbnm")
+ ans = []
+ for i in words:
+ curr = set(i.lower())
+ if curr <= l1 or curr <= l2 or curr <= l3:
+ ans.append(i)
+ return ans
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ print(obj.findWords(words=["Hello", "Alaska", "Dad", "Peace"]))
+ print(obj.findWords(words=["omk"]))
+ print(obj.findWords(words=["adsdf", "sfd"]))
diff --git a/sudoku_solver.c b/sudoku_solver.c
new file mode 100644
index 0000000..88ccc01
--- /dev/null
+++ b/sudoku_solver.c
@@ -0,0 +1,69 @@
+// 37. Sudoku Solver
+#include "leetcode.h"
+
+/*
+ * write a program to solve a sudoku puzzle by filling the empty cells. a sudoku
+ * solution must satisfy all of the following rules. each of the digits '1-9'
+ * must occur exactly once in each row, each of the digits '1-9', must occur
+ * exactly once in each column, and each of the digits '1-9' must occur exactly
+ * once in each of the 9 3x3 sub-boxes of the grid. the '.' character indicates
+ * empty cells.
+ */
+
+bool solve(char **board, bool row[9][9], bool col[9][9], bool grid[9][9], int r,
+ int c) {
+ if (r == 9)
+ return true;
+ int next_r = c == 8 ? r + 1 : r;
+ int next_c = c == 8 ? 0 : c + 1;
+ if (board[r][c] != '.')
+ return solve(board, row, col, grid, next_r, next_c);
+ int grid_idx = (r / 3) * 3 + (c / 3);
+ for (int i = 0; i < 9; i++) {
+ if (!row[r][i] && !col[c][i] && !grid[grid_idx][i]) {
+ board[r][c] = '1' + i;
+ row[r][i] = col[c][i] = grid[grid_idx][i] = true;
+ if (solve(board, row, col, grid, next_r, next_c))
+ return true;
+ board[r][c] = '.';
+ row[r][i] = col[c][i] = grid[grid_idx][i] = false;
+ }
+ }
+ return false;
+}
+
+void solveSudoku(char **board, int boardSize, int *boardColSize) {
+ if (boardSize != 9 || *boardColSize != 9)
+ return;
+ bool row[9][9] = {false};
+ bool col[9][9] = {false};
+ bool grid[9][9] = {false};
+ for (int i = 0; i < 9; i++)
+ for (int j = 0; j < 9; j++)
+ if (board[i][j] != '.') {
+ int num = board[i][j] - '1';
+ if (num < 0 || num >= 9)
+ return;
+ row[i][num] = col[j][num] = true;
+ grid[(i / 3) * 3 + (j / 3)][num] = true;
+ }
+ solve(board, row, col, grid, 0, 0);
+}
+
+int main() {
+ char *board[] = {{"5", "3", ".", ".", "7", ".", ".", ".", "."},
+ {"6", ".", ".", "1", "9", "5", ".", ".", "."},
+ {".", "9", "8", ".", ".", ".", ".", "6", "."},
+ {"8", ".", ".", ".", "6", ".", ".", ".", "3"},
+ {"4", ".", ".", "8", ".", "3", ".", ".", "1"},
+ {"7", ".", ".", ".", "2", ".", ".", ".", "6"},
+ {".", "6", ".", ".", ".", ".", "2", "8", "."},
+ {".", ".", ".", "4", "1", "9", ".", ".", "5"},
+ {".", ".", ".", ".", "8", ".", ".", "7", "9"}};
+ solveSudoku((char **)board, ARRAY_SIZE(board), ARRAY_SIZE(board[0]));
+ for (int i = 0; i < ARRAY_SIZE(board); i++) {
+ for (int j = 0; j < ARRAY_SIZE(board[0]); j++)
+ printf("%c ", board[i][j]);
+ printf("\n");
+ }
+}
diff --git a/sudoku_solver.py b/sudoku_solver.py
new file mode 100644
index 0000000..7a395e7
--- /dev/null
+++ b/sudoku_solver.py
@@ -0,0 +1,66 @@
+# 37. Sudoku Solver
+
+"""
+write a program to solve a sudoku puzzle by filling the empty cells. a sudoku
+solution must satisfy all of the following rules. each of the digits '1-9'
+must occur exactly once in each row, each of the digits '1-9', must occur
+exactly once in each column, and each of the digits '1-9' must occur exactly
+once in each of the 9 3x3 sub-boxes of the grid. the '.' character indicates
+empty cells.
+"""
+
+
+class Solution(object):
+ def solveSudoku(self, board):
+ """
+ :type board: List[List[str]]
+ :rtype: None Do not return anything, modify board in-place instead.
+ """
+ n = 9
+
+ def valid(row, col, idx):
+ row, col = int(row), int(col)
+ for i in range(9):
+ if board[i][col] == idx:
+ return False
+ if board[row][i] == idx:
+ return False
+ if board[3 * (row // 3) + i // 3][3 * (col // 3) + i % 3] == idx:
+ return False
+ return True
+
+ def solve(row, col):
+ if row == n:
+ return True
+ if col == n:
+ return solve(row + 1, 0)
+ if board[row][col] == ".":
+ for i in range(1, 10):
+ if valid(row, col, str(i)):
+ board[row][col] = str(i)
+ if solve(row, col + 1):
+ return True
+ else:
+ board[row][col] = "."
+ return False
+ else:
+ return solve(row, col + 1)
+
+ solve(0, 0)
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ board = [
+ ["5", "3", ".", ".", "7", ".", ".", ".", "."],
+ ["6", ".", ".", "1", "9", "5", ".", ".", "."],
+ [".", "9", "8", ".", ".", ".", ".", "6", "."],
+ ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+ ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+ ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+ [".", "6", ".", ".", ".", ".", "2", "8", "."],
+ [".", ".", ".", "4", "1", "9", ".", ".", "5"],
+ [".", ".", ".", ".", "8", ".", ".", "7", "9"],
+ ]
+ obj.solveSudoku(board)
+ print(board)
diff --git a/valid_sudoku.c b/valid_sudoku.c
new file mode 100644
index 0000000..dd93f60
--- /dev/null
+++ b/valid_sudoku.c
@@ -0,0 +1,55 @@
+// 36. Valid Sudoku
+#include "leetcode.h"
+
+/*
+ * determine if a 9 x 9 sudoku board is valid. only the filled cells need to be
+ * validated acording to the following rules. each row must contain the digits
+ * 1-9 without repetition, each column must contain the digits 1-9 without
+ * reptition, each of the nine 3 x 3 sub-boxes of the grid must contain the
+ * digits 1-9 without reptition. note, a sudoku board (partially filled) could
+ * be valid but it is not necessarily solvable. only the filled cells need to be
+ * validated according to the mentioned rules.
+ */
+
+bool isValidSudoku(char **board, int boardSize, int *boardColSize) {
+ bool rows[9][9] = {false};
+ bool cols[9][9] = {false};
+ bool boxes[9][9] = {false};
+ for (int i = 0; i < 9; i++) {
+ for (int j = 0; j < 9; j++) {
+ if (board[i][j] != '.') {
+ int num = board[i][j] - '1';
+ int box_idx = (i / 3) * 3 * (j / 3);
+ if (rows[i][num] || cols[j][num] || boxes[box_idx][num])
+ return false;
+ rows[i][num] = cols[j][num] = boxes[box_idx][num] = true;
+ }
+ }
+ }
+ return true;
+}
+
+int main() {
+ char *b1[] = {{"5", "3", ".", ".", "7", ".", ".", ".", "."},
+ {"6", ".", ".", "1", "9", "5", ".", ".", "."},
+ {".", "9", "8", ".", ".", ".", ".", "6", "."},
+ {"8", ".", ".", ".", "6", ".", ".", ".", "3"},
+ {"4", ".", ".", "8", ".", "3", ".", ".", "1"},
+ {"7", ".", ".", ".", "2", ".", ".", ".", "6"},
+ {".", "6", ".", ".", ".", ".", "2", "8", "."},
+ {".", ".", ".", "4", "1", "9", ".", ".", "5"},
+ {".", ".", ".", ".", "8", ".", ".", "7", "9"}};
+ char *b2[] = {{"8", "3", ".", ".", "7", ".", ".", ".", "."},
+ {"6", ".", ".", "1", "9", "5", ".", ".", "."},
+ {".", "9", "8", ".", ".", ".", ".", "6", "."},
+ {"8", ".", ".", ".", "6", ".", ".", ".", "3"},
+ {"4", ".", ".", "8", ".", "3", ".", ".", "1"},
+ {"7", ".", ".", ".", "2", ".", ".", ".", "6"},
+ {".", "6", ".", ".", ".", ".", "2", "8", "."},
+ {".", ".", ".", "4", "1", "9", ".", ".", "5"},
+ {".", ".", ".", ".", "8", ".", ".", "7", "9"}};
+ printf("%d\n",
+ isValidSudoku(b1, ARRAY_SIZE(b1), ARRAY_SIZE(b1[0]))); // expect: 1
+ printf("%d\n",
+ isValidSudoku(b2, ARRAY_SIZE(b2), ARRAY_SIZE(b2[0]))); // expect: 0
+}
diff --git a/valid_sudoku.py b/valid_sudoku.py
new file mode 100644
index 0000000..8dd758a
--- /dev/null
+++ b/valid_sudoku.py
@@ -0,0 +1,59 @@
+# 36. Valid Sudoku
+
+"""
+determine if a 9 x 9 sudoku board is valid. only the filled cells need to be
+validated acording to the following rules. each row must contain the digits
+1-9 without repetition, each column must contain the digits 1-9 without
+reptition, each of the nine 3 x 3 sub-boxes of the grid must contain the
+digits 1-9 without reptition. note, a sudoku board (partially filled) could
+be valid but it is not necessarily solvable. only the filled cells need to be
+validated according to the mentioned rules.
+"""
+
+
+class Solution(object):
+ def isValidSudoku(self, board):
+ """
+ :type board: List[List[str]]
+ :rtype: bool
+ """
+ rows = [[False] * 9 for _ in range(9)]
+ cols = [[False] * 9 for _ in range(9)]
+ boxes = [[False] * 9 for _ in range(9)]
+ for i in range(9):
+ for j in range(9):
+ if board[i][j] != ".":
+ num = ord(board[i][j] - ord("1"))
+ box_idx = (i // 3) * 3 + (j // 3)
+ if rows[i][num] or cols[j][num] or boxes[box_idx][num]:
+ return False
+ rows[i][num] = cols[j][num] = boxes[box_idx][num] = True
+ return True
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ b1 = [
+ ["5", "3", ".", ".", "7", ".", ".", ".", "."],
+ ["6", ".", ".", "1", "9", "5", ".", ".", "."],
+ [".", "9", "8", ".", ".", ".", ".", "6", "."],
+ ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+ ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+ ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+ [".", "6", ".", ".", ".", ".", "2", "8", "."],
+ [".", ".", ".", "4", "1", "9", ".", ".", "5"],
+ [".", ".", ".", ".", "8", ".", ".", "7", "9"],
+ ]
+ b2 = [
+ ["8", "3", ".", ".", "7", ".", ".", ".", "."],
+ ["6", ".", ".", "1", "9", "5", ".", ".", "."],
+ [".", "9", "8", ".", ".", ".", ".", "6", "."],
+ ["8", ".", ".", ".", "6", ".", ".", ".", "3"],
+ ["4", ".", ".", "8", ".", "3", ".", ".", "1"],
+ ["7", ".", ".", ".", "2", ".", ".", ".", "6"],
+ [".", "6", ".", ".", ".", ".", "2", "8", "."],
+ [".", ".", ".", "4", "1", "9", ".", ".", "5"],
+ [".", ".", ".", ".", "8", ".", ".", "7", "9"],
+ ]
+ print(obj.isValidSudoku(b1))
+ print(obj.isValidSudoku(b2))