short int is_bst(struct node *root) {
if (root->left == NULL)
return 1;
if (is_bst_r(root) && is_bst_l(root)) {
if ( max_right(root->right) <= root->data) {
return 1;
}
}
return 0;
}
int trap(vector<int>& height) {
int len = height.size();
vector<int> max_left(len, 0);
vector<int> max_right(len, 0);
for(int i=1; i<len; i++) {
max_left[i] = max(max_left[i-1], height[i-1]);
max_right[len-1-i] = max(max_right[len-i], height[len-i]);
}
int sum = 0;
for(int k=0; k<len;k++) {
sum += max ( min(max_left[k], max_right[k]) - height[k], 0);
}
return sum;
}
int max_right(struct node *root) {
if (root->left == NULL)
return root->data;
return max_right(root->left);
}
