Runtime error: addition of unsigned offset

I was solving a question on Leetcode (Trapping rain water) and I wrote my solution which had been tested on my local machine as well as on GeeksForGeeks where it passed all TC's. the code is:

int trap(vector<int>& height) {
    int size = height.size();
    int i,units;

    vector<int> l(size),r(size);
    l[0] = height[0];
    r[size-1] = height[size-1];
        
    for(i=1; i<size; i++){
        l[i] = max(height[i-1],l[i-1]);
    }
    
    for(i=size-1; i>=0; i--){
        r[i-1] = max(r[i],height[i]);
    }
    
    for(i=0; i<size; i++){
        if((min(l[i],r[i]) == 0) || (min(l[i],r[i])-height[i]<0))
            continue;
        else{
           units +=min(l[i],r[i])-height[i];
        }
    }
    return units;
}

This is the only part I had to edit. And upon running it I'm getting the following error

Line 928: Char 34: runtime error: addition of unsigned offset to 0x6040000000d0 overflowed to 0x6040000000cc (stl_vector.h)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_vector.h:933:34

I need some help finding where I'm experiencing a buffer overflow.

It was a typo where it should have just been i>0 instead of i>=0.