Luogu1382 楼房 (线段树 扫描线)

各种低级错误.jpg，数组开大就过.jpg

线段树离散化扫描线

#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;
}