一位数组+双分支遍历

#include <bits/stdc++.h>
using namespace std;
int main(){
    long long n,a[1010]={},sum = 0;
    cin >> n;
    for(int i = 1;i <= n;i++){
    	cin >> a[i];
	}
	for(int i = 1;i <= n;i++){
    	if(a[i]>a[i-1]){
    		sum+=a[i];
		}
		if(a[i]<a[i-1]){
			a[i] = a[i-1]+1;
			sum += a[i];
		} 
	}
	cout << sum;
    return 0;
}