spoj 138

离散化  去掉重复点 排序  二分查找

#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxn 40005

using namespace std;

int pp[maxn][2];
int x[2*maxn],f[2*maxn];
int d[2*maxn];

int main()
{
    int t;
    scanf("%d",&t);
    while (t--)
    {
        memset(f, 0 ,sizeof(0));
        int n;
        scanf("%d",&n);
        for(int i= 0; i < n; i++)
        {
            scanf("%d%d",&pp[i][0],&pp[i][1]);
            x[i] = pp[i][0];
            x[2*i+1] = pp[i][1];
        }
        sort(x, x+2*n);
        d[0] = x[0];
        int cc = 1;
        for(int i = 1; i < 2*n; i++)
        {
            if(x[i] != d[cc-1])
            {
                d[cc++] = x[i];
            }
        }
        for(int i = 0; i < n; i++)
        {
            int ri = lower_bound(d, d+cc, pp[i][0])-d;
            int le = lower_bound(d, d+cc, pp[i][1])-d;
            for(int j = ri; j <= le; j++)
                f[j] = i;
        }
        sort(f, f+cc);
        int ans = 1;
        for(int i = 1; i < cc; i++)
        {
            if(f[i] != f[i-1])
                ans++;
        }
        printf("%d\n",ans);
    }
    return 0;
}