Added Count Ways to Build Good Strings

Author: ryanoneill

Diff for: src/count_ways_to_build_good_strings.rs

@@ -0,0 +1,59 @@
+struct Solution;
+
+impl Solution {
+
+    pub fn count_good_strings(low: i32, high: i32, zero: i32, one: i32) -> i32 {
+        let low = low as usize;
+        let high = high as usize;
+        let zero = zero as usize;
+        let one = one as usize;
+
+        let mut results = vec![0; high + 1];
+        results[0] = 1;
+
+        for i in 1..=high {
+            let mut value: i64 = 0;
+            if i >= zero {
+                value += results[i - zero] as i64;
+            }
+            if i >= one {
+                value += results[i - one] as i64;
+            }
+            value = value % 1000000007;
+            results[i] = value as i32;
+        }
+        let mut result: i64 = 0;
+        for j in low..=high {
+            result += results[j] as i64;
+            result = result % 1000000007;
+        }
+        result as i32
+    }
+
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    #[test]
+    fn example_1() {
+        let low = 3;
+        let high = 3;
+        let zero = 1;
+        let one = 1;
+        let result = Solution::count_good_strings(low, high, zero, one);
+        assert_eq!(result, 8);
+    }
+
+    #[test]
+    fn example_2() {
+        let low = 2;
+        let high = 3;
+        let zero = 1;
+        let one = 2;
+        let result = Solution::count_good_strings(low, high, zero, one);
+        assert_eq!(result, 5);
+    }
+
+}

Diff for: src/lib.rs

@@ -889,6 +889,8 @@ pub mod robot_to_print_the_lexicographically_smallest_string; // 2434 ✓
 
 pub mod total_cost_to_hire_k_workers; // 2462 ✓
 
+pub mod count_ways_to_build_good_strings; // 2466 ✓
+
 pub mod circular_sentence; // 2490 ✓
 
 pub mod longest_square_streak_in_an_array; // 2501 ✓