BST——最短路径

算法：DFS:

static int sum = 0;
static int max =100;
static int i=0;
public static void pathSum(TreeNode t){
sum += t.value;
   if(t.left == null&&t.right == null){
    if(max > sum)
    max = sum;
    sum -= t.value;
    return;
   }
   if(t.left != null)

    pathSum(t.left);
   if(t.right != null)

    pathSum(t.right);
   
   sum=sum - t.value;
  
}