{"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":"Problem Statement","value":{"format":"MD","content":"给定含 N 个数和 N-1 个运算符,仅有 + 和 - 操作,的表达式。\n\n允许增加任意个合法的括号,但是:\n* 左括号必须严格紧邻在某个数左边;\n* 右括号必须严格紧邻在某个数右边。\n\n问所有可能的增加括号的方案中,修改后表达式可能的最大值是多少。"}},{"title":"Constraints","value":{"format":"MD","content":"\u003csection\u003e \n \u003cul\u003e \n \u003cli\u003e\u003cvar\u003e\\(1≦N≦10^5\\)\u003c/var\u003e\u003c/li\u003e \n \u003cli\u003e\u003cvar\u003e\\(1≦A_i≦10^9\\)\u003c/var\u003e\u003c/li\u003e \n \u003cli\u003e\u003cvar\u003e\\(op_i\\)\u003c/var\u003e is either \u003ccode\u003e+\u003c/code\u003e or \u003ccode\u003e-\u003c/code\u003e.\u003c/li\u003e \n \u003c/ul\u003e \n\u003c/section\u003e"}},{"title":"Input","value":{"format":"MD","content":"\u003csection\u003e \n \u003cp\u003eThe input is given from Standard Input in the following format:\u003c/p\u003e \n \u003cpre\u003e\u003cvar\u003e\\(N\\)\u003c/var\u003e\n\u003cvar\u003e\\(A_1\\)\u003c/var\u003e \u003cvar\u003e\\(op_1\\)\u003c/var\u003e \u003cvar\u003e\\(A_2\\)\u003c/var\u003e \u003cvar\u003e\\(...\\)\u003c/var\u003e \u003cvar\u003e\\(op_{N-1}\\)\u003c/var\u003e \u003cvar\u003e\\(A_N\\)\u003c/var\u003e\n\u003c/pre\u003e \n\u003c/section\u003e"}},{"title":"Output","value":{"format":"MD","content":"\u003csection\u003e \n \u003cp\u003ePrint the maximum possible evaluated value of the formula after inserting an arbitrary number of pairs of parentheses.\u003c/p\u003e \n\u003c/section\u003e"}},{"title":"Sample 1","value":{"format":"MD","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\u003e3\n5 - 1 - 3\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e7\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\u003csection\u003e \n \u003cp\u003eThe maximum possible value is: \u003cvar\u003e\\(5 - (1 - 3) \u003d 7\\)\u003c/var\u003e.\u003c/p\u003e \n\u003c/section\u003e"}},{"title":"Sample 2","value":{"format":"MD","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\u003e5\n1 - 2 + 3 - 4 + 5\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e5\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\u003csection\u003e \n \u003cp\u003eThe maximum possible value is: \u003cvar\u003e\\(1 - (2 + 3 - 4) + 5 \u003d 5\\)\u003c/var\u003e.\u003c/p\u003e \n\u003c/section\u003e"}},{"title":"Sample 3","value":{"format":"MD","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\u003e5\n1 - 20 - 13 + 14 - 5\n\u003c/pre\u003e\u003c/td\u003e\n \u003ctd\u003e\u003cpre\u003e13\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\u003csection\u003e \n \u003cp\u003eThe maximum possible value is: \u003cvar\u003e\\(1 - (20 - (13 + 14) - 5) \u003d 13\\)\u003c/var\u003e.\u003c/p\u003e\n\u003c/section\u003e"}}]}