Submission

Score: 100

User: pxsit

Problemset: ปริมาตรน้ำท่วม

Language: cpp

Time: 0.004 second

Submitted On: 2026-09-29 19:10:05

#include <bits/stdc++.h>
using namespace std;

int main(){
    int n;
    cin>>n;
    vector<int> h(n),pref(n),suf(n);
    for(int i=0;i<n;i++)cin>>h[i];
    pref[0]=h[0];
    for(int i=1;i<n;i++)pref[i]=max(pref[i-1],h[i]);
    suf[n-1]=h[n-1];
    for(int i=n-2;i>=0;i--)suf[i]=max(suf[i+1],h[i]);
    int sum=0;
    for(int i=0;i<n;i++)sum+=min(pref[i],suf[i])-h[i];
    cout<<sum<<endl;
    return 0;
}