luoguP1315 观光公交 题解(NOIP2011)(贪心)

P1315 观光公交 题目

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<cstring>

#include<algorithm>

#include<iomanip>

#include<ctime>

#include<queue>

#include<stack>

#define rg register

#define lst long long

#define N 1050

#define M 10050

using namespace std;

int n,m,k,num[N],u,v,w;

int down[N],up[N],ans;

int arrive[N],peo[N];

int val,idx;

inline int read()

{

    rg int s=,m=;rg char ch=getchar();

    while(ch!='-'&&(ch<''||ch>''))ch=getchar();

    if(ch=='-')m=-,ch=getchar();

    while(ch>=''&&ch<='')s=(s<<)+(s<<)+ch-'',ch=getchar();

    return s*m;

}

int main()

{

//    freopen("s.in","r",stdin);

    n=read(),m=read(),k=read();

    for(rg int i=;i<n;++i)num[i]=read();

    for(rg int i=;i<=m;++i)

    {

        u=read(),v=read(),w=read();

        ans-=u,down[w]++,up[v]=max(u,up[v]);

    }

    while(k--)

    {

        memset(peo,,sizeof(peo));

        for(rg int i=;i<=n;++i)

            arrive[i]=max(arrive[i-],up[i-])+num[i-];

        for(rg int i=n;i>=;--i)

        {

            if(num[i-])

            {

                peo[i-]=down[i];

                if(arrive[i]>up[i])

                    peo[i-]+=peo[i];

            }

            else peo[i-]=;

        }

        val=,idx=-;

        for(rg int i=;i<=n;++i)

            if(val<peo[i])val=peo[i],idx=i;

        if(idx==-)break;

        num[idx]--;

    }

    for(rg int i=;i<=n;++i)

        arrive[i]=max(arrive[i-],up[i-])+num[i-];

    for(rg int i=;i<=n;++i)ans+=arrive[i]*down[i];

    printf("%d\n",ans);

    return ;

}