NOIP 2011 Day1 Problem2

#include<cstdio>#include<iostream>using namespace std;struct node{    int color;    int cost;}a[200010];int number[60],number1[60];int main(){    freopen("hotel.in","r",stdin);    freopen("hotel.out","w",stdout);    int n,k,p;    scanf("%d %d %d",&n,&k,&p);    for(int i=1;i<=n;i++)    {        int x;        scanf("%d %d",&a[i].color,&x);        if(x>p)            a[i].cost=1;    }    int flag=0;    int sum=0;    int sum1=0;    for(int i=1;i<=n;i++)    {        sum+=number[a[i].color];        number[a[i].color]++;    }    for(int i=1;i<=n;i++)        if(a[i].cost==0)            flag=0;        else        {            if(flag==0)                memset(number1,0,sizeof(number1));            else                sum1+=number1[a[i].color];            number1[a[i].color]++;            flag=1;        }    printf("%d",sum-sum1);    return 0;}