修改目录结构，优化CMakeLists

src/2786.c

@@ -0,0 +1,9 @@
+#include <stdio.h>
+long long maxScore(int *nums, int numsSize, int x) { return 0; }
+
+int main() {
+    int nums[] = {2, 3, 6, 1, 9, 2};
+    long long result = maxScore(nums, 6, 5);
+    printf("%lld\n", result);
+    return 0;
+}