[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]);

}