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| 1 | +package warmUp_1; |
| 2 | + |
| 3 | +public class WarmUp_Solution_Two { |
| 4 | + |
| 5 | + public static void main(String[] args) { |
| 6 | + |
| 7 | + } |
| 8 | + |
| 9 | + // -------------------------------------------------------------------------------------------- |
| 10 | + |
| 11 | + // Given a string and a non-negative int n, return a larger string that is n |
| 12 | + // copies of the original string. |
| 13 | + // |
| 14 | + // |
| 15 | + // stringTimes("Hi", 2) → "HiHi" |
| 16 | + // stringTimes("Hi", 3) → "HiHiHi" |
| 17 | + // stringTimes("Hi", 1) → "Hi" |
| 18 | + |
| 19 | + public String stringTimes(String str, int n) { |
| 20 | + String result = ""; |
| 21 | + for (int i = 0; i < n; i++) { |
| 22 | + result = result + str; |
| 23 | + } |
| 24 | + return result; |
| 25 | + } |
| 26 | + |
| 27 | + // -------------------------------------------------------------------------------------------- |
| 28 | + |
| 29 | + // Given a string and a non-negative int n, we'll say that the front of the |
| 30 | + // string is the first 3 chars, or whatever is there if the string is less than |
| 31 | + // length 3. Return n copies of the front; |
| 32 | + // |
| 33 | + // |
| 34 | + // frontTimes("Chocolate", 2) → "ChoCho" |
| 35 | + // frontTimes("Chocolate", 3) → "ChoChoCho" |
| 36 | + // frontTimes("Abc", 3) → "AbcAbcAbc" |
| 37 | + |
| 38 | + public String frontTimes(String str, int n) { |
| 39 | + int frontLen = 3; |
| 40 | + if (frontLen > str.length()) { |
| 41 | + frontLen = str.length(); |
| 42 | + } |
| 43 | + String front = str.substring(0, frontLen); |
| 44 | + |
| 45 | + String result = ""; |
| 46 | + for (int i = 0; i < n; i++) { |
| 47 | + result = result + front; |
| 48 | + } |
| 49 | + return result; |
| 50 | + } |
| 51 | + |
| 52 | + // -------------------------------------------------------------------------------------------- |
| 53 | + |
| 54 | + // Count the number of "xx" in the given string. We'll say that overlapping is |
| 55 | + // allowed, so "xxx" contains 2 "xx". |
| 56 | + |
| 57 | + // countXX("abcxx") → 1 |
| 58 | + // countXX("xxx") → 2 |
| 59 | + // countXX("xxxx") → 3 |
| 60 | + |
| 61 | + int countXX(String str) { |
| 62 | + int count = 0; |
| 63 | + for (int i = 0; i < str.length() - 1; i++) { |
| 64 | + if (str.substring(i, i + 2).equals("xx")) |
| 65 | + count++; |
| 66 | + } |
| 67 | + return count; |
| 68 | + } |
| 69 | + |
| 70 | + // -------------------------------------------------------------------------------------------- |
| 71 | + |
| 72 | + // Given a string, return true if the first instance of "x" in the string is |
| 73 | + // immediately followed by another "x". |
| 74 | + |
| 75 | + // doubleX("axxbb") → true |
| 76 | + // doubleX("axaxax") → false |
| 77 | + // doubleX("xxxxx") → true |
| 78 | + |
| 79 | + boolean doubleX(String str) { |
| 80 | + int i = str.indexOf("x"); |
| 81 | + if (i == -1) |
| 82 | + return false; |
| 83 | + if (i + 1 >= str.length()) |
| 84 | + return false; |
| 85 | + return str.substring(i + 1, i + 2).equals("x"); |
| 86 | + } |
| 87 | + |
| 88 | + // -------------------------------------------------------------------------------------------- |
| 89 | + |
| 90 | + // Given a string, return a new string made of every other char starting with |
| 91 | + // the first, so "Hello" yields "Hlo". |
| 92 | + // |
| 93 | + // |
| 94 | + // stringBits("Hello") → "Hlo" |
| 95 | + // stringBits("Hi") → "H" |
| 96 | + // stringBits("Heeololeo") → "Hello" |
| 97 | + |
| 98 | + public String stringBits(String str) { |
| 99 | + String result = ""; |
| 100 | + for (int i = 0; i < str.length(); i += 2) { |
| 101 | + result = result + str.substring(i, i + 1); |
| 102 | + } |
| 103 | + return result; |
| 104 | + } |
| 105 | + |
| 106 | + // -------------------------------------------------------------------------------------------- |
| 107 | + |
| 108 | + // Given a non-empty string like "Code" return a string like "CCoCodCode". |
| 109 | + // |
| 110 | + // |
| 111 | + // stringSplosion("Code") → "CCoCodCode" |
| 112 | + // stringSplosion("abc") → "aababc" |
| 113 | + // stringSplosion("ab") → "aab" |
| 114 | + |
| 115 | + public String stringSplosion(String str) { |
| 116 | + String result = ""; |
| 117 | + for (int i = 0; i < str.length(); i++) { |
| 118 | + result = result + str.substring(0, i + 1); |
| 119 | + } |
| 120 | + return result; |
| 121 | + } |
| 122 | + |
| 123 | + // -------------------------------------------------------------------------------------------- |
| 124 | + |
| 125 | + // Given a string, return the count of the number of times that a substring |
| 126 | + // length 2 appears in the string and also as the last 2 chars of the string, so |
| 127 | + // "hixxxhi" yields 1 (we won't count the end substring). |
| 128 | + // |
| 129 | + // |
| 130 | + // last2("hixxhi") → 1 |
| 131 | + // last2("xaxxaxaxx") → 1 |
| 132 | + // last2("axxxaaxx") → 2 |
| 133 | + |
| 134 | + public int last2(String str) { |
| 135 | + if (str.length() < 2) |
| 136 | + return 0; |
| 137 | + |
| 138 | + String end = str.substring(str.length() - 2); |
| 139 | + int count = 0; |
| 140 | + for (int i = 0; i < str.length() - 2; i++) { |
| 141 | + String sub = str.substring(i, i + 2); |
| 142 | + if (sub.equals(end)) |
| 143 | + count++; |
| 144 | + } |
| 145 | + return count; |
| 146 | + } |
| 147 | + |
| 148 | + // -------------------------------------------------------------------------------------------- |
| 149 | + |
| 150 | + // |
| 151 | + // Given an array of ints, return the number of 9's in the array. |
| 152 | + // |
| 153 | + // |
| 154 | + // arrayCount9([1, 2, 9]) → 1 |
| 155 | + // arrayCount9([1, 9, 9]) → 2 |
| 156 | + // arrayCount9([1, 9, 9, 3, 9]) → 3 |
| 157 | + // |
| 158 | + public int arrayCount9(int[] nums) { |
| 159 | + int count = 0; |
| 160 | + for (int i = 0; i < nums.length; i++) { |
| 161 | + if (nums[i] == 9) { |
| 162 | + count++; |
| 163 | + } |
| 164 | + } |
| 165 | + return count; |
| 166 | + } |
| 167 | + |
| 168 | + // -------------------------------------------------------------------------------------------- |
| 169 | + |
| 170 | + // Given an array of ints, return true if one of the first 4 elements in the |
| 171 | + // array is a 9. The array length may be less than 4. |
| 172 | + // |
| 173 | + // |
| 174 | + // arrayFront9([1, 2, 9, 3, 4]) → true |
| 175 | + // arrayFront9([1, 2, 3, 4, 9]) → false |
| 176 | + // arrayFront9([1, 2, 3, 4, 5]) → false |
| 177 | + // |
| 178 | + public boolean arrayFront9(int[] nums) { |
| 179 | + |
| 180 | + int end = nums.length; |
| 181 | + if (end > 4) |
| 182 | + end = 4; |
| 183 | + |
| 184 | + for (int i = 0; i < end; i++) { |
| 185 | + if (nums[i] == 9) |
| 186 | + return true; |
| 187 | + } |
| 188 | + |
| 189 | + return false; |
| 190 | + } |
| 191 | + |
| 192 | + // -------------------------------------------------------------------------------------------- |
| 193 | + |
| 194 | + // Given an array of ints, return true if the sequence of numbers 1, 2, 3 |
| 195 | + // appears in the array somewhere. |
| 196 | + // |
| 197 | + // |
| 198 | + // array123([1, 1, 2, 3, 1]) → true |
| 199 | + // array123([1, 1, 2, 4, 1]) → false |
| 200 | + // array123([1, 1, 2, 1, 2, 3]) → true |
| 201 | + // |
| 202 | + public boolean array123(int[] nums) { |
| 203 | + if (nums.length >= 3) { |
| 204 | + for (int i = 0; i < nums.length - 2; i++) { |
| 205 | + if ((nums[i] == 1) && (nums[i + 1] == 2) && (nums[i + 2] == 3)) |
| 206 | + return true; |
| 207 | + } |
| 208 | + } |
| 209 | + return false; |
| 210 | + } |
| 211 | + |
| 212 | + // -------------------------------------------------------------------------------------------- |
| 213 | + |
| 214 | + // Given 2 strings, a and b, return the number of the positions where they |
| 215 | + // contain the same length 2 substring. So "xxcaazz" and "xxbaaz" yields 3, |
| 216 | + // since the "xx", "aa", and "az" substrings appear in the same place in both |
| 217 | + // strings. |
| 218 | + // |
| 219 | + // |
| 220 | + // stringMatch("xxcaazz", "xxbaaz") → 3 |
| 221 | + // stringMatch("abc", "abc") → 2 |
| 222 | + // stringMatch("abc", "axc") → 0 |
| 223 | + // |
| 224 | + public int stringMatch(String a, String b) { |
| 225 | + int len = Math.min(a.length(), b.length()); |
| 226 | + int count = 0; |
| 227 | + for (int i = 0; i < len - 1; i++) { |
| 228 | + String aSub = a.substring(i, i + 2); |
| 229 | + String bSub = b.substring(i, i + 2); |
| 230 | + if (aSub.equals(bSub)) { |
| 231 | + count++; |
| 232 | + } |
| 233 | + } |
| 234 | + |
| 235 | + return count; |
| 236 | + } |
| 237 | + |
| 238 | + // -------------------------------------------------------------------------------------------- |
| 239 | + |
| 240 | + // Given a string, return a version where all the "x" have been removed. Except |
| 241 | + // an "x" at the very start or end should not be removed. |
| 242 | + // |
| 243 | + // |
| 244 | + // stringX("xxHxix") → "xHix" |
| 245 | + // stringX("abxxxcd") → "abcd" |
| 246 | + // stringX("xabxxxcdx") → "xabcdx" |
| 247 | + |
| 248 | + public String stringX(String str) { |
| 249 | + String result = ""; |
| 250 | + for (int i = 0; i < str.length(); i++) { |
| 251 | + if (!(i > 0 && i < (str.length() - 1) && str.substring(i, i + 1).equals("x"))) { |
| 252 | + result = result + str.substring(i, i + 1); |
| 253 | + } |
| 254 | + } |
| 255 | + return result; |
| 256 | + } |
| 257 | + |
| 258 | + // -------------------------------------------------------------------------------------------- |
| 259 | + |
| 260 | + // Given a string, return a string made of the chars at indexes 0,1, 4,5, 8,9 |
| 261 | + // ... so "kittens" yields "kien". |
| 262 | + // |
| 263 | + // |
| 264 | + // altPairs("kitten") → "kien" |
| 265 | + // altPairs("Chocolate") → "Chole" |
| 266 | + // altPairs("CodingHorror") → "Congrr" |
| 267 | + // |
| 268 | + // |
| 269 | + public String altPairs(String str) { |
| 270 | + String result = ""; |
| 271 | + for (int i = 0; i < str.length(); i += 4) { |
| 272 | + int last = i + 2; |
| 273 | + if (last > str.length()) |
| 274 | + last = str.length(); |
| 275 | + result = result + str.substring(i, last); |
| 276 | + } |
| 277 | + return result; |
| 278 | + } |
| 279 | + |
| 280 | + // -------------------------------------------------------------------------------------------- |
| 281 | + |
| 282 | + // Suppose the string "yak" is unlucky. Given a string, return a version where |
| 283 | + // all the "yak" are removed, but the "a" can be any char. The "yak" strings |
| 284 | + // will not overlap. |
| 285 | + // |
| 286 | + // |
| 287 | + // stringYak("yakpak") → "pak" |
| 288 | + // stringYak("pakyak") → "pak" |
| 289 | + // stringYak("yak123ya") → "123ya" |
| 290 | + // |
| 291 | + |
| 292 | + public String stringYak(String str) { |
| 293 | + String result = ""; |
| 294 | + |
| 295 | + for (int i = 0; i < str.length(); i++) { |
| 296 | + if (i + 2 < str.length() && str.charAt(i) == 'y' && str.charAt(i + 2) == 'k') { |
| 297 | + i = i + 2; |
| 298 | + } else { |
| 299 | + result = result + str.charAt(i); |
| 300 | + } |
| 301 | + } |
| 302 | + return result; |
| 303 | + } |
| 304 | + |
| 305 | + // -------------------------------------------------------------------------------------------- |
| 306 | + |
| 307 | + // Given an array of ints, return the number of times that two 6's are next to |
| 308 | + // each other in the array. Also count instances where the second "6" is |
| 309 | + // actually a 7. |
| 310 | + |
| 311 | + // array667([6, 6, 2]) → 1 |
| 312 | + // array667([6, 6, 2, 6]) → 1 |
| 313 | + // array667([6, 7, 2, 6]) → 1 |
| 314 | + // |
| 315 | + // |
| 316 | + public int array667(int[] nums) { |
| 317 | + int count = 0; |
| 318 | + if (nums.length > 2) { |
| 319 | + for (int i = 0; i < nums.length - 1; i++) { |
| 320 | + if ((nums[i] == 6) && ((nums[i + 1] == 6) || (nums[i + 1] == 7))) { |
| 321 | + count++; |
| 322 | + } |
| 323 | + } |
| 324 | + } |
| 325 | + return count; |
| 326 | + } |
| 327 | + |
| 328 | + // -------------------------------------------------------------------------------------------- |
| 329 | + |
| 330 | + // Given an array of ints, we'll say that a triple is a value appearing 3 times |
| 331 | + // in a row in the array. Return true if the array does not contain any triples. |
| 332 | + // |
| 333 | + // |
| 334 | + // noTriples([1, 1, 2, 2, 1]) → true |
| 335 | + // noTriples([1, 1, 2, 2, 2, 1]) → false |
| 336 | + // noTriples([1, 1, 1, 2, 2, 2, 1]) → false |
| 337 | + // |
| 338 | + public boolean noTriples(int[] nums) { |
| 339 | + if (nums.length > 2) { |
| 340 | + for (int i = 0; i < nums.length - 2; i++) { |
| 341 | + if (nums[i] == nums[i + 1]) { |
| 342 | + if (nums[i + 1] == nums[i + 2]) |
| 343 | + return false; |
| 344 | + } |
| 345 | + } |
| 346 | + } |
| 347 | + return true; |
| 348 | + } |
| 349 | + |
| 350 | + // -------------------------------------------------------------------------------------------- |
| 351 | + |
| 352 | + // Given an array of ints, return true if it contains a 2, 7, 1 pattern: a |
| 353 | + // value, followed by the value plus 5, followed by the value minus 1. |
| 354 | + // Additionally the 271 counts even if the "1" differs by 2 or less from the |
| 355 | + // correct value. |
| 356 | + |
| 357 | + // has271([1, 2, 7, 1]) → true |
| 358 | + // has271([1, 2, 8, 1]) → false |
| 359 | + // has271([2, 7, 1]) → true |
| 360 | + |
| 361 | + public boolean has271(int[] nums) { |
| 362 | + if (nums.length > 2) { |
| 363 | + for (int i = 0; i < nums.length - 2; i++) { |
| 364 | + int first = nums[i]; |
| 365 | + if ((first + 5 == nums[i + 1]) && (Math.abs(nums[i + 2] - (first - 1)) <= 2)) |
| 366 | + return true; |
| 367 | + } |
| 368 | + } |
| 369 | + return false; |
| 370 | + } |
| 371 | + |
| 372 | +} |
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