DP优化

DP优化

单调队列优化

Watching Fireworks is Fun CF372C

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n,m,d,i,j,k,l,r,ma,f[2][150005],g[150005],a[305],b[305],c[305];
int main()
{
	cin>>n>>m>>d;
	for (i=1;i<=m;i++)
		cin>>a[i]>>b[i]>>c[i];
	memset(f,207,sizeof(f));
	for (i=1;i<=n;i++)
		f[0][i]=0;
	for (i=1;i<=m;i++)
	{
		l=1;r=0;k=1;
		for (j=1;j<=n;j++)
		{
			for (;k<=min(n,j+d*(c[i]-c[i-1]));k++)
			{
				while ((l<=r)and(f[(i-1)%2][k]>=f[(i-1)%2][g[r]])) r--;
				g[++r]=k;
			}
		while ((l<=r)and(g[l]<max(ll(1),j-d*(c[i]-c[i-1])))) l++;
		f[i%2][j]=f[(i-1)%2][g[l]]+b[i]-abs(j-a[i]);
		}
	}
	ma=-1e18;
	for (i=1;i<=n;i++)
		ma=max(ma,f[m%2][i]);
	cout<<ma<<'\n';
}