20240821 Finished

src/problem/mod.rs

@@ -212,3 +212,4 @@ mod p551_student_attendance_record_i;
 
 mod p552_student_attendance_record_ii;
 mod p3154_find_number_of_ways_to_reach_the_k_th_stair;
+mod p3007_maximum_number_that_sum_of_the_prices_is_less_than_or_equal_to_k;

src/problem/p3007_maximum_number_that_sum_of_the_prices_is_less_than_or_equal_to_k.rs

@@ -0,0 +1,60 @@
+/**
+ * [3007] Maximum Number That Sum of the Prices Is Less Than or Equal to K
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn find_maximum_number(k: i64, x: i32) -> i64 {
+        let (mut left, mut right) = (1i64, (k + 1) << x);
+
+        while left < right {
+            let middle = (left + right + 1) / 2;
+            
+            if Self::accumulate_price(x, middle) > k {
+                right = middle - 1;
+            } else {
+                left = middle;
+            }
+        }
+        
+        left
+    }
+    
+    fn accumulate_price(x: i32, num: i64) -> i64 {
+        let mut result = 0;
+        let length = 64 - i64::leading_zeros(num) as i32;
+        
+        for i in (x..=length).step_by(x as usize) {
+            result += Self::accumulate_bit_price(i, num);
+        }
+        
+        result
+    }
+    
+    fn accumulate_bit_price(x: i32, num: i64) -> i64 {
+        let period = 1i64 << x;
+        let mut result = period / 2 * (num / period);
+        
+        if num % period >= period / 2 {
+            result += num % period - (period / 2 - 1);
+        }
+        
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3007() {
+        assert_eq!(6, Solution::find_maximum_number(9, 1));
+        assert_eq!(9, Solution::find_maximum_number(7, 2));
+    }
+}