update

1 files changed, 37 insertions, 0 deletions

diff --git a/Computer_Science/leetcode/15-3_sum.c b/Computer_Science/leetcode/15-3_sum.c
new file mode 100644
index 0000000..cb60873
--- /dev/null
+++ b/Computer_Science/leetcode/15-3_sum.c
@@ -0,0 +1,37 @@
+/**
+ * Return an array of arrays of size *returnSize.
+ * Note: The returned array must be malloced, assume caller calls free().
+ */
+void helper(int **result, int *nums, int start, int numsSize, int *tmp, int count, int *returnSize)
+{
+	if(start >= numsSize) return;
+	if(count < 3) {
+		tmp[count] = nums[start];
+		helper(result, nums, start + 1, numsSize, tmp, count + 1, returnSize);
+	}
+	else if(count == 3) {
+		if(tmp[0] + tmp[1] + tmp[2] == 0) {
+			*(result + *returnSize) = malloc(sizeof(int) * 3);
+			**(result + *returnSize) = tmp[0];
+			*(*(result + *returnSize) + 1) = tmp[1];
+			*(*(result + *returnSize) + 2) = tmp[2];
+			++*returnSize;
+		}
+		helper(result, nums, start, numsSize, tmp, count - 1, returnSize);
+		helper(result, nums, start, numsSize, tmp, count - 2, returnSize);
+	}
+
+}
+
+int** threeSum(int* nums, int numsSize, int* returnSize) {
+	*returnSize = 0;
+	int **result = malloc(sizeof(int *) * 100);
+	int tmp[3];
+	int count = 0;
+	
+	for(int i = 0; i < numsSize; i++) {
+		helper(result, nums, i, numsSize, tmp, 0, returnSize);
+	}
+
+	return result;
+}