Search for a range

Signed-off-by: begeekmyfriend <[email protected]>

034_search_for_a_range/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test range_search.c

034_search_for_a_range/range_search.c

@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+static int binary_search_start(int *a, int size, int target)
+{
+    int low = -1;
+    int high = size;
+    while (low + 1 < high) {
+        int mid = low + (high - low) / 2;
+        if (target > a[mid]) {
+            low = mid;
+        } else {
+            high = mid;
+        }
+    }
+
+    if (high == size || a[high] != target) {
+        return -1;
+    } else {
+        return high;
+    }
+}
+
+static int binary_search_end(int *a, int size, int target)
+{
+    int low = -1;
+    int high = size;
+    while (low + 1 < high) {
+        int mid = low + (high - low) / 2;
+        if (target < a[mid]) {
+            high = mid;
+        } else {
+            low = mid;
+        }
+    }
+
+    if (low == -1 || a[low] != target) {
+        return -1;
+    } else {
+        return low;
+    }
+}
+
+/**
+ ** Return an array of size *returnSize.
+ ** Note: The returned array must be malloced, assume caller calls free().
+ **/
+int* searchRange(int* nums, int numsSize, int target, int* returnSize) {
+    int *range = malloc(2 * sizeof(int));
+
+    if (numsSize == 0) {
+        range[0] = range[1] = -1;
+        return range;
+    }
+
+    range[0] = binary_search_start(nums, numsSize, target);
+    range[1] = binary_search_end(nums, numsSize, target);
+    *returnSize = 2;    
+    return range;
+}
+
+int main(int argc, char **argv)
+{
+    int i, count;
+    int *nums = malloc((argc - 2) * sizeof(int));
+    for (i = 0; i < argc - 2; i++) {
+        nums[i] = atoi(argv[i + 2]);
+    }
+
+    int *range = searchRange(nums, argc - 2, atoi(argv[1]), &count);
+    printf("%d %d\n", range[0], range[1]);
+
+    return 0;
+}