{"trustable":true,"prependHtml":"\u003cstyle type\u003d\"text/css\"\u003e\n div.illustration {\n float: right;\n padding-left: 20px;\n }\n div.illustration .illustration {\n width: 100%;\n border-radius: 4px;\n }\n pre {\n display: block;\n margin: 0 0 10px;\n font-size: 13px;\n line-height: 1.42857143;\n color: #333;\n word-break: break-all;\n word-wrap: break-word;\n }\n\u003c/style\u003e\n\u003cscript\u003e\n window.katexOptions \u003d {\n delimiters: [\n {left: \u0027\\\\[\u0027, right: \u0027\\\\]\u0027, display: true}\n ]\n };\n\u003c/script\u003e\n","sections":[{"title":"","value":{"format":"HTML","content":"\n \u003cp\u003eYou are given two strings \u003cspan class\u003d\"tex2jax_process\"\u003e$s$\u003c/span\u003e, and \u003cspan class\u003d\"tex2jax_process\"\u003e$t$\u003c/span\u003e. Count the number of substrings of\n \u003cspan class\u003d\"tex2jax_process\"\u003e$s$\u003c/span\u003e that contain\n \u003cspan class\u003d\"tex2jax_process\"\u003e$t$\u003c/span\u003e as a subsequence at\n least once.\u003c/p\u003e\n \u003cp\u003eNote that a \u003cspan class\u003d\"tex2jax_process\"\u003e$substring$\u003c/span\u003e\n and a \u003cspan class\u003d\"tex2jax_process\"\u003e$subsequence$\u003c/span\u003e both\n consist of characters from the original string, in order. In a\n \u003cspan class\u003d\"tex2jax_process\"\u003e$substring$\u003c/span\u003e, the\n characters must be contiguous in the original string, but in a\n \u003cspan class\u003d\"tex2jax_process\"\u003e$subsequence$\u003c/span\u003e, they are\n not required to be contiguous. In the string \u003cb class\u003d\"bf\"\u003eabcde\u003c/b\u003e, \u003cb class\u003d\"bf\"\u003eace\u003c/b\u003e is a \u003ci class\u003d\"itshape\"\u003esubsequence\u003c/i\u003e but not a \u003ci class\u003d\"itshape\"\u003esubstring\u003c/i\u003e.\u003c/p\u003e\n \u003cp\u003eIf \u003cspan class\u003d\"tex2jax_process\"\u003e$s$\u003c/span\u003e is \u003cb class\u003d\"bf\"\u003eaa\u003c/b\u003e and \u003cspan class\u003d\"tex2jax_process\"\u003e$t$\u003c/span\u003e is\n \u003cb class\u003d\"bf\"\u003ea\u003c/b\u003e, then the answer is \u003cspan class\u003d\"tex2jax_process\"\u003e$3$\u003c/span\u003e: \u003cb class\u003d\"bf\"\u003e[a]a\u003c/b\u003e, \u003cb class\u003d\"bf\"\u003e[aa]\u003c/b\u003e, and \u003cb class\u003d\"bf\"\u003ea[a]\u003c/b\u003e.\u003c/p\u003e\n \u003ch2\u003eInput\u003c/h2\u003e\n \u003cp\u003eEach test case will consist of exactly two lines.\u003c/p\u003e\n \u003cp\u003eThe first line will contain string \u003cspan class\u003d\"tex2jax_process\"\u003e$s$\u003c/span\u003e (\u003cspan class\u003d\"tex2jax_process\"\u003e$1\\! \\le \\! |s|\\! \\le \\! 10^5, s\\! \\in \\!\n [a{-}z]^*$\u003c/span\u003e), with no other characters.\u003c/p\u003e\n \u003cp\u003eThe second line will contain string \u003cspan class\u003d\"tex2jax_process\"\u003e$t$\u003c/span\u003e (\u003cspan class\u003d\"tex2jax_process\"\u003e$1\\! \\le \\! |t|\\! \\le \\! 100, |t|\\! \\le \\!\n |s|, t\\! \\in \\! [a{-}z]^*$\u003c/span\u003e), with no other\n characters.\u003c/p\u003e\n \u003ch2\u003eOutput\u003c/h2\u003e\n \u003cp\u003eOutput a single integer, which is the number of substrings\n of \u003cspan class\u003d\"tex2jax_process\"\u003e$s$\u003c/span\u003e that contain\n \u003cspan class\u003d\"tex2jax_process\"\u003e$t$\u003c/span\u003e as a subsequence at\n least once.\u003c/p\u003e\n \u003ch2\u003eSample 1\u003c/h2\u003e\u003cbody\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003eabcdefghijklmnopqrstuvwxyz\na\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e26\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/body\u003e\n \u003ch2\u003eSample 2\u003c/h2\u003e\u003cbody\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003eabcdefghijklmnopqrstuvwxyz\nm\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e182\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/body\u003e\n \u003ch2\u003eSample 3\u003c/h2\u003e\u003cbody\u003e\u003ctable class\u003d\"vjudge_sample\"\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\u003epenpineappleapplepen\nppap\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e68\n\u003c/pre\u003e\u003c/td\u003e\n \u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/body\u003e\n "}}]}