[agc011F]Train Service Planning-[线段树优化dp+神秘思考题]

Description

传送门

Solution

请围观lhx大佬的博客（大佬写的太好了我都没有写的动力了em）

Code

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
typedef long long ll;
int n,k;
int a[],b[];
ll sum[];
int L[],R[],t[];
ll dp[];

int tag[];
void downtag(int k)
{
    tag[k<<]=tag[k<<|]=tag[k];
    tag[k]=;
}
void modify(int k,int l,int r,int askx,int asky,int x)
{
    if (askx>asky) return;
    if (askx<=l&&r<=asky) {tag[k]=x;return;}
    int mid=(l+r)/;
    if (tag[k]) downtag(k);
    if (askx<=mid) modify(k<<,l,mid,askx,asky,x);
    if (mid<asky) modify(k<<|,mid+,r,askx,asky,x);
}
int query(int k,int l,int r,int x)
{
    if (l==r) return tag[k];
    int mid=(l+r)/;
    if (tag[k]) downtag(k);
    if (mid>=x) return query(k<<,l,mid,x);
    else return query(k<<|,mid+,r,x);
}
int cnt;
ll solve(int x){
    int re=query(,,cnt,x);
    if (!re) return ;
    return dp[re]+((long long)t[L[re]]-t[x]+k)%k;
}
int main()
{
    scanf("%d%d",&n,&k);
    for (int i=;i<=n;i++)
    {
        scanf("%d%d",&a[i],&b[i]);
        sum[i]=a[i]+sum[i-];
        if (b[i]!=) continue;
        if (*a[i]>k) {puts("-1");return ;}
    }
    for (int i=;i<=n;i++)
    {
        if (b[i]==)
        {
            L[i]=(-*sum[i-]%k+k)%k;
            R[i]=(-*sum[i]%k+k)%k;
        }else L[i]=,R[i]=k-;
        t[i*-]=L[i],t[i*]=R[i];
    }
    sort(t+,t+*n+);
    cnt=unique(t+,t+*n+)-t-;
    for (int i=n;i;i--)
    {
        L[i]=lower_bound(t+,t+cnt+,L[i])-t;
        R[i]=lower_bound(t+,t+cnt+,R[i])-t;
        dp[i]=solve(L[i]);
        if (L[i]>R[i]) modify(,,cnt,R[i]+,L[i]-,i);
        else modify(,,cnt,,L[i]-,i),modify(,,cnt,R[i]+,cnt,i);
    }
    ll ans=1e14;
    for (int i=;i<=cnt;i++) ans=min(ans,solve(i));
    printf("%lld",ans+*sum[n]);
}