NC 16593 暴力

题意

传送门 NC 16593

题解

从最大编号地毯向下枚举，$O(n)$ 判断覆盖 $(x,y)$ 的最上方点编号。

#include 
#include 
#include 
#include 
using namespace std;

#define maxn 10005
struct rect
{
    int x1, y1, x2, y2;
    rect() {}
    rect(int x1, int y1, int x2, int y2) : x1(x1), y1(y1), x2(x2), y2(y2) {}
    bool inside(int x, int y)
    {
        return x >= x1 && x <= x2 && y >= y1 && y <= y2;
    }
};
rect rs[maxn];

int main()
{
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
    {
        int a, b, g, k;
        scanf("%d%d%d%d", &a, &b, &g, &k);
        rs[i] = rect(a, b, a + g, b + k);
    }
    int x, y, res = -1;
    scanf("%d%d", &x, &y);
    for (int i = n - 1; i >= 0; i--)
    {
        if (rs[i].inside(x, y))
        {
            res = i + 1;
            break;
        }
    }
    printf("%d\n", res);
    return 0;
}