class Solution {
public:
    int trap(vector<int>& height) {
    int n = height.size();
   
    int maxleft[n];
    
    int maxright[n];    
    
    maxleft[0] = height[0];
    
    maxright[n-1] = height[n-1];
    
    for(int i=1;i<n;i++)
    {
        maxleft[i] = max(height[i],maxleft[i-1]);  
    }    
    
    for(int i=n-2;i>=0;i--)
    {
        maxright[i] = max(height[i],maxright[i+1]) ; 
    }    
    
    int water[n];
    
    for(int i=0;i<n;i++)        
    {
        water[i] = min(maxleft[i],maxright[i])-height[i];
    }
    int sum=0;    
    
    for(int i=0;i<n;i++)        
    {
        sum +=water[i];
    }
    return sum;    
    }
};