poj2528 线段树+骚气的离散化姿势

by cww97

因为这个图所以，不能当做左闭右开的线段树来做

and，卡了两个小时是因为

这个傻逼错误

//for (int i = 1; i <= A; i++) {
//  x[a[i]] = i;//啊啊啊啊啊啊啊啊啊啊啊啊啊啊
    //printf("x[%d] = %d\n", a[i], i);
//}

T.build(A);
for (int i = 1; i <= n; i++){
    int L = lower_bound(a+1, a+A+1, l[i]) - a;//x[l[i]]
    int R = lower_bound(a+1, a+A+1, r[i]) - a;//x[r[i]]
    //printf("(%d, %d)\n", L, R);
    T.update(L, R, i, 1, T.M+1,1);
}

妈的离散化忘了用lower_bound，还开数组存

发现错误前怀疑数据

发现错误后被自己蠢哭

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long LL;
const int N = 2e5 + 7;

int l[N], r[N], n;
int a[N], A, x[N];
bool vis[N];
int ans;

struct segmentTree
{
    #define lc (rt<<1)
    #define rc (rt<<1^1)
    #define lson l, m, rt<<1
    #define rson m+1, r, rt<<1^1
    int M, col[N];

    inline void build(int n){
        M = 1; while(M<n)M<<=1; M--;
        memset(col, 0, sizeof(col));
    }

    inline void pushDown(int rt){
        if (col[rt] == 0) return;
        col[lc] = col[rc] = col[rt];
        col[rt] = 0;
    }

    inline void update(int L, int R, int x, int l, int r, int rt){
        if (L <= l && r <= R){
            col[rt] = x;
            return;
        }
        pushDown(rt);
        int m = (l + r) >> 1;
        if (L <= m) update(L, R, x, lson);
        if (m <  R) update(L, R, x, rson);
    }

    inline int query(int rt){
        if (col[rt] > 0) {
            if (vis[col[rt]]) return 0;
            vis[col[rt]] = 1;
            return 1;
        }
        if (rt > M) return 0;
        int ans = 0;
        ans += query(lc);
        ans += query(rc);
        return ans;
    }
} T;

int main(){
    //freopen("in.txt", "r", stdin);
    int _;
    scanf("%d", &_);
    for (;_--;){
        scanf("%d", &n);
        A = 0;
        for (int i = 1; i <= n; i++){
            scanf("%d%d", &l[i], &r[i]);
            a[++A] = l[i];
            a[++A] = r[i];
        }
        sort(a + 1, a + A+1);
        A = unique(a + 1, a + A+1) - (a + 1);
        for (int i = A; i > 1; i--){
            if (a[i-1] + 1 < a[i]) a[++A] = a[i-1] + 1;
        }
        sort(a + 1, a + A+1);

        T.build(A);
        for (int i = 1; i <= n; i++){
            int L = lower_bound(a+1, a+A+1, l[i]) - a;
            int R = lower_bound(a+1, a+A+1, r[i]) - a;
            T.update(L, R, i, 1, T.M+1,1);
        }
        ans = 0;
        memset(vis, 0, sizeof(vis));
        printf("%d\n", T.query(1));
    }
    return 0;
}