Luogu1382 楼房 (线段树 扫描线)

Posted 2022-04-29 bingoyes

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long

//#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\\n\\n----------\\n\\n")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")

#else

#define D_e_Line ;

#endif

struct ios
    template<typename ATP>ios& operator >> (ATP &x)
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    
io;
using namespace std;
#define lson rt << 1, l, mid
#define rson rt << 1 | 1, mid + 1, r

const int N = 400007;

int t[N << 2];
// do not need pushup
inline void Pushdown(int rt)
    t[rt << 1] = Max(t[rt << 1], t[rt]);
    t[rt << 1 | 1] = Max(t[rt << 1 | 1], t[rt]);

inline void Updata(int rt, int l, int r, int L, int R, int w)
    if(L <= l && r <= R)
        t[rt] = Max(t[rt], w);
        return;
    
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(L <= mid) Updata(lson, L, R, w);
    if(R > mid)  Updata(rson, L, R, w);

inline int Query(int rt, int l, int r, int x)
    if(l == r) return t[rt];
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(x <= mid) return Query(lson, x);
    else return Query(rson, x);


int x[N], y[N], h[N];
int a[N << 1];
int main()
    int n;
    io >> n;
    R(i,1,n)
        io >> h[i] >> x[i] >> y[i];
        a[(i << 1) - 1] = x[i];
        a[i << 1] = y[i];
    
    
    sort(a + 1, a + (n << 1) + 1);
    int m = unique(a + 1, a + (n << 1) + 1) - a - 1;
    
    R(i,1,n)
        x[i] = lower_bound(a + 1, a + m + 1, x[i]) - a;
        y[i] = lower_bound(a + 1, a + m + 1, y[i]) - a;
        
        Updata(1, 1, m, x[i], y[i] - 1, h[i]); // how can I miss m as n, how can I ! how can I ! Ahhhhhhhhhhhhhhhhhhh
        
    
    int tot = 0, last = 0;
    x[++tot] = a[1];
    y[tot] = 0;
    R(i,1,m - 1)
        int H = Query(1, 1, m, i);
        if(H != last)
            x[++tot] = a[i];
            y[tot] = H;
            x[++tot] = a[i + 1];
            y[tot] = H;
        
        else
            x[tot] = a[i + 1];
        
        last = H;
    
    
    printf("%d\\n", tot + 1);
    R(i,1,tot)
        printf("%d %d\\n", x[i], y[i]);
    
    printf("%d 0", a[m]);
    
    return 0;