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authorjack <[email protected]>2024-06-14 13:13:15 -0600
committerjack <[email protected]>2024-06-14 13:13:15 -0600
commitd343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch)
tree96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /sum_abs_diff_arr.c
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+// 1685. Sum of Absolute Differences in a Sorted Array
+#include "leetcode.h"
+
+/*
+ * you are given an integer array 'nums' sorted in non-decreasing order. build
+ * and return an integer array 'result' with the same length as 'nums' such that
+ * 'result[i] is equal to the summation of absolute differences between 'nums[i]
+ * and all the other elements in the array. in other words, 'result[i] is equal
+ * to 'sum(|nums[i] - nums[j]|) where '0 <= j < nums.length()' and 'j != i'.
+ */
+
+int *getSumAbsoluteDifferences(int *nums, int nums_size, int *return_size) {
+ *return_size = nums_size;
+ int sum = 0, tmp_sum = 0;
+ for (int i = 0; i < nums_size; i++)
+ sum += nums[i];
+ int *ans = (int *)malloc(nums_size * sizeof(int));
+ for (int i = 0; i < nums_size; i++) {
+ tmp_sum += nums[i];
+ int tmp = sum + (2 * i - nums_size) * nums[i];
+ ans[i] = !i ? tmp : tmp - 2 * (tmp_sum - nums[i]);
+ }
+ return ans;
+}
+
+int main() {
+ int n1[] = {2, 3, 5}, n2[] = {1, 4, 6, 8, 10};
+ int rs1[] = {}, rs2[] = {};
+ int *gsad1 = getSumAbsoluteDifferences(n1, ARRAY_SIZE(n1), rs1);
+ int *gsad2 = getSumAbsoluteDifferences(n2, ARRAY_SIZE(n2), rs2);
+ for (int i = 0; i < ARRAY_SIZE(n1); i++)
+ printf("%d ", gsad1[i]); // expect: 4 3 5
+ printf("\n");
+ for (int i = 0; i < ARRAY_SIZE(n2); i++)
+ printf("%d ", gsad2[i]); // expect: 24 15 13 15 21
+ printf("\n");
+}