1589. Maximum Sum Obtained of Any Permutation: AC

Author: tan-wei

src/solution/mod.rs

@@ -1197,3 +1197,4 @@ mod s1583_count_unhappy_friends;
 mod s1584_min_cost_to_connect_all_points;
 mod s1585_check_if_string_is_transformable_with_substring_sort_operations;
 mod s1588_sum_of_all_odd_length_subarrays;
+mod s1589_maximum_sum_obtained_of_any_permutation;

src/solution/s1589_maximum_sum_obtained_of_any_permutation.rs

@@ -0,0 +1,119 @@
+/**
+ * [1589] Maximum Sum Obtained of Any Permutation
+ *
+ * We have an array of integers, nums, and an array of requests where requests[i] = [starti, endi]. The i^th request asks for the sum of nums[starti] + nums[starti + 1] + ... + nums[endi - 1] + nums[endi]. Both starti and endi are 0-indexed.
+ * Return the maximum total sum of all requests among all permutations of nums.
+ * Since the answer may be too large, return it modulo 10^9 + 7.
+ *  
+ * Example 1:
+ *
+ * Input: nums = [1,2,3,4,5], requests = [[1,3],[0,1]]
+ * Output: 19
+ * Explanation: One permutation of nums is [2,1,3,4,5] with the following result:
+ * requests[0] -> nums[1] + nums[2] + nums[3] = 1 + 3 + 4 = 8
+ * requests[1] -> nums[0] + nums[1] = 2 + 1 = 3
+ * Total sum: 8 + 3 = 11.
+ * A permutation with a higher total sum is [3,5,4,2,1] with the following result:
+ * requests[0] -> nums[1] + nums[2] + nums[3] = 5 + 4 + 2 = 11
+ * requests[1] -> nums[0] + nums[1] = 3 + 5  = 8
+ * Total sum: 11 + 8 = 19, which is the best that you can do.
+ *
+ * Example 2:
+ *
+ * Input: nums = [1,2,3,4,5,6], requests = [[0,1]]
+ * Output: 11
+ * Explanation: A permutation with the max total sum is [6,5,4,3,2,1] with request sums [11].
+ * Example 3:
+ *
+ * Input: nums = [1,2,3,4,5,10], requests = [[0,2],[1,3],[1,1]]
+ * Output: 47
+ * Explanation: A permutation with the max total sum is [4,10,5,3,2,1] with request sums [19,18,10].
+ *  
+ * Constraints:
+ *
+ * 	n == nums.length
+ * 	1 <= n <= 10^5
+ * 	0 <= nums[i] <= 10^5
+ * 	1 <= requests.length <= 10^5
+ * 	requests[i].length == 2
+ * 	0 <= starti <= endi < n
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/maximum-sum-obtained-of-any-permutation/
+// discuss: https://leetcode.com/problems/maximum-sum-obtained-of-any-permutation/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+const MOD: usize = 1_000_000_007;
+
+impl Solution {
+    pub fn max_sum_range_query(nums: Vec<i32>, requests: Vec<Vec<i32>>) -> i32 {
+        let n = nums.len();
+        let mut memo = vec![(0, 0); n];
+
+        for arr in requests {
+            memo[arr[0] as usize].0 += 1;
+            memo[arr[1] as usize].1 += 1;
+        }
+
+        let mut counts = vec![0; n];
+        let mut temp = 0;
+        for i in 0..n {
+            temp += memo[i].0;
+            counts[i] = temp;
+            temp -= memo[i].1;
+        }
+
+        counts.sort_unstable();
+        let mut nums = nums;
+        nums.sort_unstable();
+
+        let mut result = 0;
+
+        for i in 0..n {
+            result += counts[i] as usize * nums[i] as usize % MOD;
+            result %= MOD;
+        }
+
+        result as i32
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1589_example_1() {
+        let nums = vec![1, 2, 3, 4, 5];
+        let requests = vec![vec![1, 3], vec![0, 1]];
+
+        let result = 19;
+
+        assert_eq!(Solution::max_sum_range_query(nums, requests), result);
+    }
+
+    #[test]
+    fn test_1589_example_2() {
+        let nums = vec![1, 2, 3, 4, 5, 6];
+        let requests = vec![vec![0, 1]];
+
+        let result = 11;
+
+        assert_eq!(Solution::max_sum_range_query(nums, requests), result);
+    }
+
+    #[test]
+    fn test_1589_example_3() {
+        let nums = vec![1, 2, 3, 4, 5, 10];
+        let requests = vec![vec![0, 2], vec![1, 3], vec![1, 1]];
+
+        let result = 47;
+
+        assert_eq!(Solution::max_sum_range_query(nums, requests), result);
+    }
+}