luoguP1311 选择客栈 题解(NOIP2011)

P1311 选择客栈  题目

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<iomanip>
#include<algorithm>
#include<queue>
#include<ctime>
#define ll long long
#define rg register
#define N 200050
using namespace std;

int n,m,p;
ll ans;
struct house{
    int col,v;
}ljl[N];
int f[N][],last[N];

inline int read()
{
    int s=,m=;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;
}

void init()
{
    n=read();m=read();p=read();
    for(int i=;i<=n;++i)
    {
        ljl[i].col=read();
        ljl[i].v=read();
    }
    int la=;
    for(int i=;i<=n;++i)
    {
        if(ljl[i].v<=p)la=i;
        for(int j=;j<=;++j)
        {
            f[i][j]=f[i-][j];
        }
        last[i]=la;
        f[i][ljl[i].col]=f[i-][ljl[i].col]+;
    }
}

void work()
{
    for(int i=;i<=n;++i)
    {
        ans+=f[last[i]][ljl[i].col];
        if(last[i]==i)ans--;
    }
}

int main()
{
    init();
    work();
    cout<<ans<<endl;
    return ;
}