海底高铁70WA 求调

跟着猴哥の题解写的，只有70分

求调

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;

long long n, m, p[N], a[N], b[N], c[N], d[N], ans;

int main()
{
	cin >> n >> m;
	for (int i = 1; i <= m; i++)
		cin >> p[i];
	for (int i = 1; i <= n - 1; i++)
		cin >> a[i] >> b[i] >> c[i];
	
	for (int i = 1; i <= m - 1; i++)
	{
		int l = min(p[i], p[i + 1]), r = max(p[i], p[i + 1]);
		d[l]++, d[r]--;
	}
	
	for (int i = 1; i <= n - 1; i++)
		d[i] += d[i - 1];
	
	for (int i = 1; i <= n - 1; i++)
	{
		int noBuy = d[i] * a[i], buy = d[i] * b[i] + c[i];
		ans += min(noBuy, buy);
	}
	
	cout << ans;
	
	return 0;
}