{"problem":{"name":"[SDCPC 2023] Orders","description":{"content":"A factory receives $n$ orders at the beginning of day $1$. The $i$-th order can be described as two integers $a_i$ and $b_i$, indicating that at the end of day $a_i$, the factory needs to deliver $b_i","description_type":"Markdown"},"platform":"Luogu","limit":{"time_limit":1000,"memory_limit":1048576},"difficulty":{"LuoguStyle":"P2"},"is_remote":true,"is_sync":true,"sync_url":null,"sign":"LGP9556"},"statements":[{"statement_type":"Markdown","content":"A factory receives $n$ orders at the beginning of day $1$. The $i$-th order can be described as two integers $a_i$ and $b_i$, indicating that at the end of day $a_i$, the factory needs to deliver $b_i$ products to the customer.\n\nGiven that the factory can produce $k$ products each day, and at the beginning of day $1$ the factory has no product in stock, can the factory complete all orders?\n\n## Input\n\nThere are multiple test cases. The first line of the input contains an integer $T$ ($1 \\le T \\le 100$) indicating the number of test cases. For each test case:\n\nThe first line contains two integers $n$ and $k$ ($1 \\le n \\le 100$, $1 \\le k \\le 10^9$) indicating the number of orders and the number of products the factory can produce each day.\n\nFor the following $n$ lines, the $i$-th line contains two integers $a_i$ and $b_i$ ($1 \\le a_i, b_i \\le 10^9$) indicating that the $i$-th order require the factory to deliver $b_i$ products at the end of day $a_i$.\n\n## Output\n\nFor each test case output one line. If the factory can complete all orders output $\\texttt{Yes}$, otherwise output $\\texttt{No}$.\n\n[samples]\n\n## Note\n\nFor the first sample test case, the factory can produce $5$ products each day.\n\n- At the end of day $1$, there are $5$ products in stock so the factory can complete the $2$-nd order. After delivery, there are $2$ products left in stock.\n- At the end of day $6$, the factory produces $25$ more products. There are $27$ products in stock so the factory can complete the $1$-st and the $3$-rd order. After delivery, there are $0$ products left in stock.\n- At the end of day $8$, the factory produces $10$ more products. There are $10$ products in stock so the factory can complete the $4$-th order. After delivery, there are $9$ products left in stock.\n\nFor the second sample test case, the factory can produce $100$ products each day.\n\n- At the end of day $3$, there are $300$ products in stock and the factory can complete the $1$-st order. After delivery, there are $100$ products left in stock.\n- At the end of day $4$, the factory produces $100$ more products. There are only $200$ products in stock so the factory cannot complete the $2$-nd order.","is_translate":false,"language":"English"}],"meta":{"iden":"LGP9556","tags":["2023","山东","O2优化","省赛/邀请赛"],"sample_group":[["2\n4 5\n6 12\n1 3\n6 15\n8 1\n3 100\n3 200\n4 300\n6 100","Yes\nNo"]],"created_at":"2026-03-03 11:09:25"}}