poj 2528 Mayor's posters

线段树+离散化处理。

写的我好蛋疼啊！！！

不过总算过了。

/*
POJ: 2528 Mayor's posters 
*/
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <functional>

using namespace std;

const int MaxN = 10005;
const int TreeSize = 100005;

struct SegmentTree {
    int left, right;
    int poster;
} tree[TreeSize];

struct Descrete {
    int point, num;
    
    bool operator < (const struct Descrete &t) const {
        return point < t.point; 
    }
} des[2 * MaxN];

bool visible[MaxN];
int n;
int seg[2 * MaxN][2];
int ans;

void init(int i, int a, int b)
{
    tree[i].left = a;
    tree[i].right = b;
    tree[i].poster = -1;

    if(a < b) {
        int mid = (a + b) >> 1;
        init(2 * i, a, mid);
        init(2 * i + 1, mid + 1, b);
    }
}

void insert(int i, int a, int b, int p)
{
    if(tree[i].left >= a && tree[i].right <= b) {
        tree[i].poster = p;
        return ;
    }
    
    if(tree[i].poster > 0) {
        tree[2 * i].poster = tree[i].poster;
        tree[2 * i + 1].poster = tree[i].poster;
        tree[i].poster = -1;
    }
    
    int mid = (tree[i].left + tree[i].right) >> 1;
    if(b <= mid)
        insert(2 * i, a, b, p);
    else if(a > mid)
        insert(2 * i + 1, a, b, p);
    else {
        insert(2 * i, a, mid, p);
        insert(2 * i + 1, mid + 1, b, p);
    }
}

void find(int i)
{
    if(tree[i].poster > 0) {
        if(!visible[tree[i].poster]) {
            ans++;
            visible[tree[i].poster] = true;
        }
        return ;
    }
    
    find(2 * i);
    find(2 * i + 1);
}

int main()
{
    //freopen("data.in", "rb", stdin);
    int c;
    scanf("%d", &c);
    while(c--) {      
        scanf("%d", &n);
        
        for(int i = 0; i < n; i++) {
            scanf("%d%d", &des[i * 2].point, &des[i * 2 + 1].point);
            des[i * 2].num = -(i + 1);
            des[i * 2 + 1].num = i + 1;
        }
        
        sort(des, des + 2 * n);
        
        int total = 1;
        int tmp = des[0].point;
        for(int i = 0; i < 2 * n; i++) {
            if(des[i].point != tmp) {
                total++;
                tmp = des[i].point;
            }
            if(des[i].num < 0)
                seg[-des[i].num][0] = total;
            else
                seg[des[i].num][1] = total;
        }
        
        init(1, 1, total);
        for(int i = 1; i <= n; i++)
            insert(1, seg[i][0], seg[i][1], i + 1);
        
        memset(visible, false, sizeof(visible));
        ans = 0;
        find(1);
        
        printf("%d\n", ans);
    }
    
    return 0;
}