{"trustable":false,"sections":[{"title":"","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n 在二维平面给出很多棍子,求在最上面的棍子(不被覆盖)\n \u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n 多组数据. 每组数据第一行为n (1 \u0026lt;\u003d n \u0026lt;\u003d 100000),代表棍子的数量. 接下来n行每行输入两个点,代表一个棍子(重合的两根棍子,后面输入的棍子在上面),保证答案不超过1000. n\u003d0代表输入结束\n \u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n 每组数据输入最上面的棍子\n \u003cbr\u003e \n \u003cbr\u003e下图解释了第一组输入\n \u003cimg SRC\u003d\"CDN_BASE_URL/ccc924a09f253a1bb9a3bc88c231cf8f?v\u003d1565068761\" align\u003d\"right\"\u003e\n \u003c/div\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e5\n1 1 4 2\n2 3 3 1\n1 -2.0 8 4\n1 4 8 2\n3 3 6 -2.0\n3\n0 0 1 1\n1 0 2 1\n2 0 3 1\n0\n\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003eTop sticks: 2, 4, 5.\nTop sticks: 1, 2, 3.\n\u003c/pre\u003e"}},{"title":"Hint","value":{"format":"HTML","content":"建议使用scanf"}}]}