20241112 finished.

src/problem/mod.rs

@@ -310,3 +310,5 @@ mod p3242_design_neighbor_sum_service;
 mod p540_single_element_in_a_sorted_array;
 
 mod p1547_minimum_cost_to_cut_a_stick;
+
+mod p3258_count_substrings_that_satisfy_k_constraint_i;

src/problem/p3258_count_substrings_that_satisfy_k_constraint_i.rs

@@ -0,0 +1,76 @@
+/**
+ * [3258] Count Substrings That Satisfy K-Constraint I
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn count_k_constraint_substrings(s: String, k: i32) -> i32 {
+        let s: Vec<u32> = s.chars().map(|x| x.to_digit(10).unwrap()).collect();
+
+        let mut result = 0;
+        let mut windows = Vec::with_capacity(s.len());
+
+        let mut window = (0, 0);
+        for i in 0..s.len() {
+            if s[i] == 0 {
+                window.0 += 1;
+            } else {
+                window.1 += 1;
+            }
+
+            windows.push(window);
+            if window.0 <= k || window.1 <= k {
+                result += 1;
+            }
+        }
+
+        for i in 1..s.len() {
+            for length in 1..=s.len() {
+                if i >= length {
+                    if s[i] == 0 {
+                        windows[length - 1].0 += 1;
+                    } else {
+                        windows[length - 1].1 += 1;
+                    }
+
+                    if s[i - length] == 0 {
+                        windows[length - 1].0 -= 1;
+                    } else {
+                        windows[length - 1].1 -= 1;
+                    }
+
+                    if windows[length - 1].0 <= k || windows[length - 1].1 <= k {
+                        result += 1;
+                    }
+                }
+            }
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3258() {
+        assert_eq!(
+            12,
+            Solution::count_k_constraint_substrings("10101".to_owned(), 1)
+        );
+        assert_eq!(
+            25,
+            Solution::count_k_constraint_substrings("1010101".to_owned(), 2)
+        );
+        assert_eq!(
+            15,
+            Solution::count_k_constraint_substrings("11111".to_owned(), 1)
+        );
+    }
+}