diff --git a/src/arr.rs b/src/arr.rs
index d6ac3e5..6c4493c 100644
--- a/src/arr.rs
+++ b/src/arr.rs
@@ -79,3 +79,126 @@ pub fn make_matrix(s: &str) -> Vec<Vec<i32>> {
 
     rows
 }
+
+pub fn make_char_matrix(s: &str) -> Vec<Vec<char>> {
+    let s = s.trim();
+
+    // Remove only the outermost pair of brackets if present, e.g. "[[1,2],[3,4]]" -> "[1,2],[3,4]"
+    let inner = if s.len() >= 2 && s.starts_with('[') && s.ends_with(']') {
+        &s[1..s.len() - 1]
+    } else {
+        s
+    }
+        .trim();
+
+    if inner.is_empty() {
+        return Vec::new();
+    }
+
+    let bytes = inner.as_bytes();
+    let mut i = 0usize;
+    let mut rows: Vec<Vec<char>> = Vec::new();
+    while i < bytes.len() {
+        // find next '['
+        while i < bytes.len() && bytes[i] != b'[' {
+            i += 1;
+        }
+        if i >= bytes.len() {
+            break;
+        }
+        let start = i + 1; // byte index after '['
+        i = start;
+        // find matching ']'
+        while i < bytes.len() && bytes[i] != b']' {
+            i += 1;
+        }
+        let end = i; // exclusive
+        // move i past ']' for next iteration (if in bounds)
+        if i < bytes.len() {
+            i += 1;
+        }
+
+        if end <= start {
+            // empty row like []
+            rows.push(Vec::new());
+            continue;
+        }
+
+        let row_str = &inner[start..end];
+        let row_vec: Vec<char> = row_str
+            .split(',')
+            .map(|x| {
+                let x = x.trim().trim_matches('"');
+                if x == "null" || x.is_empty() {
+                    ' '
+                } else {
+                    x.to_string().chars().nth(0).unwrap()
+                }
+            })
+            .collect();
+        rows.push(row_vec);
+    }
+
+    rows
+}
+pub fn make_string_matrix(s: &str) -> Vec<Vec<String>> {
+    let s = s.trim();
+
+    // Remove only the outermost pair of brackets if present, e.g. "[[1,2],[3,4]]" -> "[1,2],[3,4]"
+    let inner = if s.len() >= 2 && s.starts_with('[') && s.ends_with(']') {
+        &s[1..s.len() - 1]
+    } else {
+        s
+    }
+        .trim();
+
+    if inner.is_empty() {
+        return Vec::new();
+    }
+
+    let bytes = inner.as_bytes();
+    let mut i = 0usize;
+    let mut rows: Vec<Vec<String>> = Vec::new();
+    while i < bytes.len() {
+        // find next '['
+        while i < bytes.len() && bytes[i] != b'[' {
+            i += 1;
+        }
+        if i >= bytes.len() {
+            break;
+        }
+        let start = i + 1; // byte index after '['
+        i = start;
+        // find matching ']'
+        while i < bytes.len() && bytes[i] != b']' {
+            i += 1;
+        }
+        let end = i; // exclusive
+        // move i past ']' for next iteration (if in bounds)
+        if i < bytes.len() {
+            i += 1;
+        }
+
+        if end <= start {
+            // empty row like []
+            rows.push(Vec::new());
+            continue;
+        }
+
+        let row_str = &inner[start..end];
+        let row_vec: Vec<String> = row_str
+            .split(',')
+            .map(|x| {
+                let x = x.trim().trim_matches('"');
+                if x == "null" || x.is_empty() {
+                    "".to_string()
+                } else {
+                    x.to_string()
+                }
+            })
+            .collect();
+        rows.push(row_vec);
+    }
+
+    rows
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 44e4f83..a4ee6ad 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,29 +1,53 @@
 struct Solution;
 mod arr;
 impl Solution {
-    pub fn count_submatrices(mut grid: Vec<Vec<i32>>, k: i32) -> i32 {
+    pub fn number_of_submatrices(mut grid: Vec<Vec<char>>) -> i32 {
+        let mut arr = vec![vec![(0, 0); grid[0].len()]; grid.len()];
+        match grid[0][0] {
+            '.' => arr[0][0] = (0, 0),
+            'X' => arr[0][0] = (0, 1),
+            'Y' => arr[0][0] = (1, 0),
+            _ => {}
+        }
         let mut ans = 0;
-        if grid[0][0] <= k {
-            ans += 1;
-        }else {
-            return 0;
-        }
         for i in 1..grid[0].len() {
-            grid[0][i] += grid[0][i-1];
-            if grid[0][i] <= k {
+            let (mut y, mut x) = arr[0][i - 1];
+            match grid[0][i] {
+                'X' => x += 1,
+                'Y' => y += 1,
+                _ => {}
+            }
+            if x == y && x != 0 {
                 ans += 1;
             }
+            arr[0][i] = (y, x)
         }
-        for i in 1.. grid.len() {
-            grid[i][0] += grid[i-1][0];
-            if grid[i][0] <= k {
+
+        for i in 1..grid.len() {
+            let (mut y, mut x) = arr[i - 1][0];
+            match grid[i][0] {
+                'X' => x += 1,
+                'Y' => y += 1,
+                _ => {}
+            }
+            arr[i][0] = (y, x);
+            if x == y && x != 0 {
                 ans += 1;
             }
-            for j in 1.. grid[i].len() {
-                grid[i][j] += grid[i-1][j] + grid[i][j-1] - grid[i-1][j-1];
-                if grid[i][j] <= k {
+            for j in 1..grid[i].len() {
+                let (ya, xa) = arr[i - 1][j];
+                let (yb, xb) = arr[i][j - 1];
+                let (yc, xc) = arr[i - 1][j - 1];
+                let (mut x, mut y) = (xa + xb - xc, ya + yb - yc);
+                match grid[i][j] {
+                    'X' => x += 1,
+                    'Y' => y += 1,
+                    _ => {}
+                }
+                if x == y && x != 0 {
                     ans += 1;
                 }
+                arr[i][j] = (y, x);
             }
         }
         ans
@@ -31,9 +55,6 @@ impl Solution {
 }
 
 fn main() {
-    let result = Solution::count_submatrices(arr::make_matrix(
-        "[[7,2,9],[1,5,0],[2,6,6]]"
-    ), 20);
-
+    let result = Solution::number_of_submatrices(arr::make_char_matrix(r#"[["X","Y"],["X","Y"]]"#));
     println!("{:?}", result);
 }