為了提高使用 C++ 語言寫題的能力，最近在用 C++ 語言寫 USACO 題目，逐漸適應新語言，另外也複習基本忘完的 OI 知識。
這道題我完全採用的暴力搜索方法，代碼也寫得毫無美感。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | /* ID: cxj6661 LANG: C++ PROG: calfflac */ #include <iostream> #include <fstream> #include <string> using namespace std; char lower(char source) { if (source < 'a') return source + 'a' - 'A'; return source; } int main(void) { ifstream fin("calfflac.in"); ofstream fout("calfflac.out"); char c; string s(""); while (!fin.eof ()) { c = fin.get(); s += c; } int max = 0, ms = 0, l, r, me = 0, len = s.length (), all = 0, maxall = 0; for (unsigned int i = 0; i < len; ++i) { if (!isalpha(s[i])) continue; l = i; r = i; int j = 0; all = 1; while (true) { ++r; --l; if ((r >= len) || l < 0) break; while (!isalpha(s[r])) { ++r; if (r >= len) break; } while (!isalpha(s[l])) { --l; if (l < 0) break; } all += 2; ++j; if (r >= len || l < 0) break; if (lower(s[r]) != lower(s[l])) break; if (maxall < all) { max = j; ms = l; me = r; maxall = all; } } l = i; r = i + 1; while (!isalpha(s[r])) { r++; if (r >= len) break; } if (r >= len) continue; if (s[r] != s[l]) continue; j = 0; all = 2; while (true) { ++r; --l; if ((r >= len) || l < 0) break; while (!isalpha(s[r])) { ++r; if (r >= len) break; } while (!isalpha(s[l])) { --l; if (l < 0) break; } all += 2; ++j; if (r >= len || l < 0) break; if (lower(s[r]) != lower(s[l])) break; if (maxall < all) { max = j; ms = l; me = r; maxall = all; } } } fout << maxall << endl << s.substr(ms, me - ms + 1) << endl; return 0; } |
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