2180. 统计各位数字之和为偶数的整数个数

难度

• Easy
• Medium
• Hard

思路

之前写过一次，这回用个不一样的方法（指打表）。

代码

class Solution:
    def countEven(self, num: int) -> int:
        nums = [0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 30, 30, 31, 31, 32, 32, 33, 33, 34, 34, 34, 35, 35, 36, 36, 37, 37, 38, 38, 39, 40, 40, 41, 41, 42, 42, 43, 43, 44, 44, 44, 45, 45, 46, 46, 47, 47, 48, 48, 49, 49, 50, 50, 51, 51, 52, 52, 53, 53, 54, 55, 55, 56, 56, 57, 57, 58, 58, 59, 59, 59, 60, 60, 61, 61, 62, 62, 63, 63, 64, 65, 65, 66, 66, 67, 67, 68, 68, 69, 69, 69, 70, 70, 71, 71, 72, 72, 73, 73, 74, 75, 75, 76, 76, 77, 77, 78, 78, 79, 79, 79, 80, 80, 81, 81, 82, 82, 83, 83, 84, 85, 85, 86, 86, 87, 87, 88, 88, 89, 89, 89, 90, 90, 91, 91, 92, 92, 93, 93, 94, 95, 95, 96, 96, 97, 97, 98, 98, 99, 99, 100, 100, 101, 101, 102, 102, 103, 103, 104, 104, 104, 105, 105, 106, 106, 107, 107, 108, 108, 109, 110, 110, 111, 111, 112, 112, 113, 113, 114, 114, 114, 115, 115, 116, 116, 117, 117, 118, 118, 119, 120, 120, 121, 121, 122, 122, 123, 123, 124, 124, 124, 125, 125, 126, 126, 127, 127, 128, 128, 129, 130, 130, 131, 131, 132, 132, 133, 133, 134, 134, 134, 135, 135, 136, 136, 137, 137, 138, 138, 139, 140, 140, 141, 141, 142, 142, 143, 143, 144, 144, 144, 145, 145, 146, 146, 147, 147, 148, 148, 149, 149, 150, 150, 151, 151, 152, 152, 153, 153, 154, 155, 155, 156, 156, 157, 157, 158, 158, 159, 159, 159, 160, 160, 161, 161, 162, 162, 163, 163, 164, 165, 165, 166, 166, 167, 167, 168, 168, 169, 169, 169, 170, 170, 171, 171, 172, 172, 173, 173, 174, 175, 175, 176, 176, 177, 177, 178, 178, 179, 179, 179, 180, 180, 181, 181, 182, 182, 183, 183, 184, 185, 185, 186, 186, 187, 187, 188, 188, 189, 189, 189, 190, 190, 191, 191, 192, 192, 193, 193, 194, 195, 195, 196, 196, 197, 197, 198, 198, 199, 199, 200, 200, 201, 201, 202, 202, 203, 203, 204, 204, 204, 205, 205, 206, 206, 207, 207, 208, 208, 209, 210, 210, 211, 211, 212, 212, 213, 213, 214, 214, 214, 215, 215, 216, 216, 217, 217, 218, 218, 219, 220, 220, 221, 221, 222, 222, 223, 223, 224, 224, 224, 225, 225, 226, 226, 227, 227, 228, 228, 229, 230, 230, 231, 231, 232, 232, 233, 233, 234, 234, 234, 235, 235, 236, 236, 237, 237, 238, 238, 239, 240, 240, 241, 241, 242, 242, 243, 243, 244, 244, 244, 245, 245, 246, 246, 247, 247, 248, 248, 249, 249, 250, 250, 251, 251, 252, 252, 253, 253, 254, 255, 255, 256, 256, 257, 257, 258, 258, 259, 259, 259, 260, 260, 261, 261, 262, 262, 263, 263, 264, 265, 265, 266, 266, 267, 267, 268, 268, 269, 269, 269, 270, 270, 271, 271, 272, 272, 273, 273, 274, 275, 275, 276, 276, 277, 277, 278, 278, 279, 279, 279, 280, 280, 281, 281, 282, 282, 283, 283, 284, 285, 285, 286, 286, 287, 287, 288, 288, 289, 289, 289, 290, 290, 291, 291, 292, 292, 293, 293, 294, 295, 295, 296, 296, 297, 297, 298, 298, 299, 299, 300, 300, 301, 301, 302, 302, 303, 303, 304, 304, 304, 305, 305, 306, 306, 307, 307, 308, 308, 309, 310, 310, 311, 311, 312, 312, 313, 313, 314, 314, 314, 315, 315, 316, 316, 317, 317, 318, 318, 319, 320, 320, 321, 321, 322, 322, 323, 323, 324, 324, 324, 325, 325, 326, 326, 327, 327, 328, 328, 329, 330, 330, 331, 331, 332, 332, 333, 333, 334, 334, 334, 335, 335, 336, 336, 337, 337, 338, 338, 339, 340, 340, 341, 341, 342, 342, 343, 343, 344, 344, 344, 345, 345, 346, 346, 347, 347, 348, 348, 349, 349, 350, 350, 351, 351, 352, 352, 353, 353, 354, 355, 355, 356, 356, 357, 357, 358, 358, 359, 359, 359, 360, 360, 361, 361, 362, 362, 363, 363, 364, 365, 365, 366, 366, 367, 367, 368, 368, 369, 369, 369, 370, 370, 371, 371, 372, 372, 373, 373, 374, 375, 375, 376, 376, 377, 377, 378, 378, 379, 379, 379, 380, 380, 381, 381, 382, 382, 383, 383, 384, 385, 385, 386, 386, 387, 387, 388, 388, 389, 389, 389, 390, 390, 391, 391, 392, 392, 393, 393, 394, 395, 395, 396, 396, 397, 397, 398, 398, 399, 399, 400, 400, 401, 401, 402, 402, 403, 403, 404, 404, 404, 405, 405, 406, 406, 407, 407, 408, 408, 409, 410, 410, 411, 411, 412, 412, 413, 413, 414, 414, 414, 415, 415, 416, 416, 417, 417, 418, 418, 419, 420, 420, 421, 421, 422, 422, 423, 423, 424, 424, 424, 425, 425, 426, 426, 427, 427, 428, 428, 429, 430, 430, 431, 431, 432, 432, 433, 433, 434, 434, 434, 435, 435, 436, 436, 437, 437, 438, 438, 439, 440, 440, 441, 441, 442, 442, 443, 443, 444, 444, 444, 445, 445, 446, 446, 447, 447, 448, 448, 449, 449, 450, 450, 451, 451, 452, 452, 453, 453, 454, 455, 455, 456, 456, 457, 457, 458, 458, 459, 459, 459, 460, 460, 461, 461, 462, 462, 463, 463, 464, 465, 465, 466, 466, 467, 467, 468, 468, 469, 469, 469, 470, 470, 471, 471, 472, 472, 473, 473, 474, 475, 475, 476, 476, 477, 477, 478, 478, 479, 479, 479, 480, 480, 481, 481, 482, 482, 483, 483, 484, 485, 485, 486, 486, 487, 487, 488, 488, 489, 489, 489, 490, 490, 491, 491, 492, 492, 493, 493, 494, 495, 495, 496, 496, 497, 497, 498, 498, 499, 499, 499];
        return nums[num]