Man?Man?I????WhatcanIsay?Whatfucknitamade

sb雨水

#include<bits/stdc++.h>
using namespace std;
vector<int>height;
int main(){
	int n;
	cin>>n;
	for(int i=1;i<=n;i++){
		int x;cin>>x;
		height.push_back(x);
	}
	if(height.size()==0)cout<<0;
	else{
        stack<int> s;
        int ans=0;
        int t;
        for(int i=0;i<height.size();i++)
        {
            while(s.size()&&height[s.top()]<height[i])
            {
                t=s.top();
                s.pop();
                if(!s.size())break;
                int l=s.top();
                int r=i;
                int w=r-l-1;
                ans+=(min(height[i],height[l])-height[t])*w;
            }
            s.push(i);
        }
        cout<<ans;
	}
	return 0;
}