update prob 1

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

leetcode/problem_1/sol1.c

@@ -1,3 +1,25 @@
+/**
+ * \file
+ * \brief [1. Twos Sum](https://leetcode.com/problems/two-sum/) solution
+ * \details
+ * Given an array of integers `nums` and an integer `target`, return **indices
+ * of the two numbers such that they add up to `target`**.
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/**
+ * @brief Solution implementation
+ *
+ * @param [in] nums array of integers
+ * @param [in] numsSize number of integers in the array
+ * @param [in] target target integer
+ * @param [out] returnSize size of output array (always = 2)
+ * @return int* array
+ * @note the output array must be **freed** by the calling function.
+ */
 int *twoSum(int *nums, int numsSize, int target, int *returnSize)
 {
     int i, j;
@@ -15,3 +37,33 @@ int *twoSum(int *nums, int numsSize, int target, int *returnSize)
     *returnSize = 2;
     return ret;
 }
+
+/** Main function
+ * @returns 0
+ */
+int main()
+{
+    int in1[] = {2, 7, 11, 15};
+    int target1 = 9;
+    int tmp;
+    int *test1 = twoSum(in1, 4, target1, &tmp);
+    assert(in1[test1[0]] + in1[test1[1]] == target1);
+    printf("Test 1 passed.\n");
+    free(test1);
+
+    int in2[] = {3, 2, 4};
+    int target2 = 6;
+    int *test2 = twoSum(in2, 3, target2, &tmp);
+    assert(in2[test2[0]] + in2[test2[1]] == target2);
+    printf("Test 2 passed.\n");
+    free(test2);
+
+    int in3[] = {3, 3};
+    int target3 = 6;
+    int *test3 = twoSum(in3, 2, target3, &tmp);
+    assert(in3[test3[0]] + in3[test3[1]] == target3);
+    printf("Test 3 passed.\n");
+    free(test3);
+
+    return 0;
+}