{"trustable":false,"prependHtml":"\u003cstyle type\u003d\"text/css\"\u003e\n section pre {\n display: block;\n padding: 9.5px;\n margin: 0 0 10px;\n font-size: 13px;\n line-height: 1.42857143;\n word-break: break-all;\n word-wrap: break-word;\n color: #333;\n background: rgba(255, 255, 255, 0.5);\n border: 1px solid #ccc;\n border-radius: 6px;\n }\n\u003c/style\u003e\n\u003cscript\u003e\n window.katexOptions \u003d {\n delimiters: [\n {left: \u0027\\\\(\u0027, right: \u0027\\\\)\u0027, display: false},\n {left: \u0027\\\\[\u0027, right: \u0027\\\\]\u0027, display: true}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"Bài toán","value":{"format":"HTML","content":"\u003csection\u003e\n\u003cp\u003eCó một bậc thang với \u003cvar\u003e\\(N\\)\u003c/var\u003e bậc. Tèo đang đứng ở chân cầu thang, tức là ở bậc thứ \u003cvar\u003e\\(0\\)\u003c/var\u003e.\nAnh ta có thể bước lên một hoặc hai bậc mỗi lần.\u003c/p\u003e\n\u003cp\u003eTuy nhiên, các bậc thang thứ \u003cvar\u003e\\(a_1\\)\u003c/var\u003e, \u003cvar\u003e\\(a_2\\)\u003c/var\u003e, \u003cvar\u003e\\(a_3\\)\u003c/var\u003e, \u003cvar\u003e\\(\\ldots\\)\u003c/var\u003e, \u003cvar\u003e\\(a_M\\)\u003c/var\u003e bị hỏng, vì vậy rất nguy hiểm khi đặt chân lên những bậc đó.\u003c/p\u003e\n\u003cp\u003eCó bao nhiêu cách để bước lên bậc cuối cùng, tức là bậc thứ \u003cvar\u003e\\(N\\)\u003c/var\u003e, mà không đặt chân lên những bậc bị hỏng?\nTìm số cách theo modulo \u003cvar\u003e\\(1\\ 000\\ 000\\ 007\\)\u003c/var\u003e.\u003c/p\u003e\n\u003c/section\u003e"}},{"title":"Ràng buộc","value":{"format":"HTML","content":"\u003csection\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cvar\u003e\\(1 \\leq N \\leq 10^5\\)\u003c/var\u003e\u003c/li\u003e\n\u003cli\u003e\u003cvar\u003e\\(0 \\leq M \\leq N-1\\)\u003c/var\u003e\u003c/li\u003e\n\u003cli\u003e\u003cvar\u003e\\(1 \\leq a_1 \u0026lt; a_2 \u0026lt; \\)\u003c/var\u003e \u003cvar\u003e\\(...\\)\u003c/var\u003e \u003cvar\u003e\\( \u0026lt; a_M \\leq N-1\\)\u003c/var\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/section\u003e"}},{"title":"Dữ liệu","value":{"format":"HTML","content":"\u003csection\u003e\n\u003cp\u003eDữ liệu nhập vào theo định dạng sau:\u003c/p\u003e\n\u003cpre\u003e\u003cvar\u003e\\(N\\)\u003c/var\u003e \u003cvar\u003e\\(M\\)\u003c/var\u003e\n\u003cvar\u003e\\(a_1\\)\u003c/var\u003e\n\u003cvar\u003e\\(a_2\\)\u003c/var\u003e\n\u003cvar\u003e\\( .\\)\u003c/var\u003e\n\u003cvar\u003e\\( .\\)\u003c/var\u003e\n\u003cvar\u003e\\( .\\)\u003c/var\u003e\n\u003cvar\u003e\\(a_M\\)\u003c/var\u003e\n\u003c/pre\u003e\n\u003c/section\u003e"}},{"title":"Kết quả","value":{"format":"HTML","content":"\u003csection\u003e\n\u003cp\u003eIn ra số cách để bước lên cầu thang theo điều kiện, theo modulo \u003cvar\u003e\\(1\\ 000\\ 000\\ 007\\)\u003c/var\u003e.\u003c/p\u003e\n\u003c/section\u003e"}},{"title":"Ví dụ 1","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e6 1\n3\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e4\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003csection\u003e\n\u003c/section\u003e\n\u003csection\u003e\n\u003cp\u003eCó bốn cách để bước lên cầu thang, như sau:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cvar\u003e\\(0 \\to 1 \\to 2 \\to 4 \\to 5 \\to 6\\)\u003c/var\u003e\u003c/li\u003e\n\u003cli\u003e\u003cvar\u003e\\(0 \\to 1 \\to 2 \\to 4 \\to 6\\)\u003c/var\u003e\u003c/li\u003e\n\u003cli\u003e\u003cvar\u003e\\(0 \\to 2 \\to 4 \\to 5 \\to 6\\)\u003c/var\u003e\u003c/li\u003e\n\u003cli\u003e\u003cvar\u003e\\(0 \\to 2 \\to 4 \\to 6\\)\u003c/var\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/section\u003e"}},{"title":"Ví dụ 2","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e10 2\n4\n5\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e0\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003csection\u003e\n\u003c/section\u003e\n\u003csection\u003e\n\u003cp\u003eCó thể không có cách nào để bước lên cầu thang mà không đặt chân lên các bậc bị hỏng.\u003c/p\u003e\n\u003c/section\u003e"}},{"title":"Ví dụ 3","value":{"format":"HTML","content":"\u003ctable class\u003d\u0027vjudge_sample\u0027\u003e\n\u003cthead\u003e\n \u003ctr\u003e\n \u003cth\u003eInput\u003c/th\u003e\n \u003cth\u003eOutput\u003c/th\u003e\n \u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\u003cpre\u003e100 5\n1\n23\n45\n67\n89\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e608200469\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003csection\u003e\n\u003c/section\u003e\n\u003csection\u003e\n\u003cp\u003eHãy chắc chắn in ra số cách theo modulo \u003cvar\u003e\\(1\\ 000\\ 000\\ 007\\)\u003c/var\u003e.\u003c/p\u003e\n\u003c/section\u003e"}}]}