leetcode

commit 3cd1b5564145691e318084324b1c7827181ba79b
parent 6f4ebe95ad9890f3ed441ff4d037f2c63be0888a
Author: Jack Sangdahl <jack@pngu.org>
Date:   Tue,  3 Mar 2026 20:02:53 -0700

1582. special positions in a binary matrix

Diffstat:
M
special_position_binary_matrix.c
 | 
56
++++++++++++++++++++++++++++++--------------------------
M
special_position_binary_matrix.py
 | 
27
+++++++++++++++++++--------

2 files changed, 49 insertions(+), 34 deletions(-)
diff --git a/special_position_binary_matrix.c b/special_position_binary_matrix.c
@@ -7,35 +7,39 @@
  * other elements in a row and column are 0
  */
 
-// int numSpecial(int **mat, int mat_size, int *mat_col_size) {
-int numSpecial(int r, int c, int mat[r][c], int mat_size, int *mat_col_size) {
-  int cnt = 0;
-  for (int rows = 0; rows < mat_size; rows++)
-    for (int cols = 0; cols < *mat_col_size; cols++)
-      if (mat[rows][cols]) {
-        bool match = 1;
-        for (int i = 0; i < *mat_col_size; i++)
-          if (mat[rows][i] && i != cols) {
-            match = 0;
-            break;
-          }
-        if (!match)
-          break;
-        for (int i = 0; i < mat_size; i++)
-          if (mat[i][cols] && i != rows) {
-            match = 0;
-            break;
-          }
-        if (match)
-          cnt++;
+int numSpecial(int **mat, int matSize, int *matColSize) {
+  int n = matSize, m = matColSize[0];
+  int *row_sum = (int *)calloc(n, sizeof(int));
+  int *col_sum = (int *)calloc(m, sizeof(int));
+  for (int i = 0; i < n; i++)
+    for (int j = 0; j < m; j++)
+      if (mat[i][j]) {
+        row_sum[i]++;
+        col_sum[j]++;
       }
+  int cnt = 0;
+  for (int i = 0; i < n; i++)
+    for (int j = 0; j < m; j++)
+      if (mat[i][j] && row_sum[i] == 1 && col_sum[j] == 1)
+        cnt++;
+  free(row_sum);
+  free(col_sum);
   return cnt;
 }
 
 int main() {
-  int m1[3][3] = {{1, 0, 0}, {0, 0, 1}, {1, 0, 0}},
-      m2[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
-  int mcs1[] = {}, mcs2[] = {};
-  printf("%d\n", numSpecial(3, 3, m1, 3, mcs1)); // expect: 1
-  printf("%d\n", numSpecial(3, 3, m1, 3, mcs2)); // expect: 3
+  int m1i[3][3] = {{1, 0, 0}, {0, 0, 1}, {1, 0, 0}};
+  int m2i[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
+  struct two_d_arr *m1 =
+      two_d_arr_init(ARRAY_SIZE(m1i), ARRAY_SIZE(m1i[0]), m1i);
+  struct two_d_arr *m2 =
+      two_d_arr_init(ARRAY_SIZE(m2i), ARRAY_SIZE(m2i[0]), m2i);
+  int r1 = numSpecial(m1->arr, m1->row_size, m1->col_size);
+  int r2 = numSpecial(m2->arr, m2->row_size, m2->col_size);
+  printf("%d\n", r1); // expect: 1
+  assert(r1 == 1);
+  printf("%d\n", r2); // expect: 3
+  assert(r2 == 3);
+  two_d_arr_free(m1);
+  two_d_arr_free(m2);
 }
diff --git a/special_position_binary_matrix.py b/special_position_binary_matrix.py
@@ -1,4 +1,5 @@
 # 1582. Special Positions in a Binary Matrix
+from typing import List
 
 """
 given an 'm  n' binary matrix 'mat', return the number of special positions
@@ -7,15 +8,25 @@ other elements in a row and column are 0
 """
 
 
-class Solution(object):
-    def numSpecial(self, mat):
-        """
-        :type mat: List[List[int]]
-        :rtype: int
-        """
+class Solution:
+    def numSpecial(self, mat: List[List[int]]) -> int:
+        col_idx = [0] * len(mat)
+        row_sum = [0] * len(mat)
+        col_sum = [0] * len(mat[0])
+        for r, row in enumerate(mat):
+            for c, col in enumerate(mat[r]):
+                if col:
+                    row_sum[r] += 1
+                    col_sum[c] += 1
+                    col_idx[r] = c
+        cnt = 0
+        for i, j in enumerate(row_sum):
+            if j == 1 and col_sum[col_idx[i]] == 1:
+                cnt += 1
+        return cnt
 
 
 if __name__ == "__main__":
     obj = Solution()
-    print(obj.numSpecial(mat=[[1, 0, 0], [0, 0, 1], [1, 0, 0]]))  # expect: 1
-    print(obj.numSpecial(mat=[[1, 0, 0], [0, 1, 0], [0, 0, 1]]))  # expect: 3
+    print(obj.numSpecial(mat=[[1, 0, 0], [0, 0, 1], [1, 0, 0]]))
+    print(obj.numSpecial(mat=[[1, 0, 0], [0, 1, 0], [0, 0, 1]]))