Maximal Square

Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>

Author: begeekmyfriend

221_maximal_square/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test maximal_square.c

221_maximal_square/maximal_square.c

@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static inline int min(int a, int b)
+{
+    return a < b ? a : b;
+}
+
+static inline int max(int a, int b)
+{
+    return a > b ? a : b;
+}
+
+static int maximalSquare(char** matrix, int matrixRowSize, int matrixColSize)
+{
+    int i, j, max_len = 0;
+    int **lens = malloc(matrixRowSize * sizeof(int *));
+    for (i = 0; i < matrixRowSize; i++) {
+        lens[i] = malloc(matrixColSize * sizeof(int));
+    }
+
+    for (i = 0; i < matrixColSize; i++) {
+        lens[0][i] = matrix[0][i] == '1' ? 1 : 0;
+        max_len = matrix[0][i] == '1' ? 1 : max_len;
+    }
+
+    for (i = 0; i < matrixRowSize; i++) {
+        lens[i][0] = matrix[i][0] == '1' ? 1 : 0;
+        max_len = matrix[i][0] == '1' ? 1 : max_len;
+    }
+
+    for (i = 1; i < matrixRowSize; i++) {
+        for (j = 1; j < matrixColSize; j++) {
+            if (matrix[i][j] == '1') {
+                lens[i][j] = 1;
+                lens[i][j] += min(lens[i - 1][j - 1], min(lens[i - 1][j], lens[i][j - 1]));
+            } else {
+                lens[i][j] = 0;
+            }
+            max_len = max(max_len, lens[i][j]);
+        }
+    }
+    return max_len * max_len;
+}
+
+/* ./test 11111111 11111110 11111110 11111000 01111000 */
+int main(int argc, char **argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: ./test row1 row2...\n");
+        exit(-1);
+    }
+
+    int i, j;
+    int row_size = argc - 1;
+    int col_size = strlen(argv[1]);
+    for (i = 0; i < row_size; i++) {
+        printf("%s\n", argv[i + 1]);
+    }
+    printf("%d\n", maximalSquare(argv + 1, argc - 1, strlen(argv[1])));
+    return 0;
+}