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-rw-r--r--find_k_closest_elements.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/find_k_closest_elements.c b/find_k_closest_elements.c
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+// 658. Find K Closest Elements
+#include "leetcode.h"
+
+/*
+ * given a sorted integer array 'arr', two integers 'k' and 'x', return the 'k'
+ * closest integers to 'x' in the array. the result should also be sorted in
+ * ascending order. an integer 'a' is closer to 'x' than an integer 'b' if '|a -
+ * x| < |b - x|' or '|a - x| == |b - x|' and 'a < b'.
+ */
+
+int *findClosestElements(int *arr, int arrSize, int k, int x, int *returnSize) {
+ int l = 0, r = arrSize - k;
+ while (l < r) {
+ int m = (l + r) / 2;
+ if (x - arr[m] > arr[m + k] - x)
+ l = m + 1;
+ else
+ r = m;
+ }
+ int *k_closest = (int *)calloc(k, sizeof(int));
+ *returnSize = k;
+ for (int i = 0; i < k; i++)
+ k_closest[i] = arr[l++];
+ return k_closest;
+}
+
+int main() {
+ int a1[] = {1, 2, 3, 4, 5}, a2[] = {1, 2, 3, 4, 5}, rs1, rs2;
+ int *fce1 = findClosestElements(a1, ARRAY_SIZE(a1), 4, 3, &rs1);
+ int *fce2 = findClosestElements(a2, ARRAY_SIZE(a2), 4, -1, &rs2);
+ for (int i = 0; i < rs1; i++)
+ printf("%d ", fce1[i]); // expect: 1 2 3 4
+ printf("\n");
+ for (int i = 0; i < rs2; i++)
+ printf("%d ", fce2[i]); // expect: 1 2 3 4
+ printf("\n");
+ free(fce1), free(fce2);
+}