强行模拟即可，且数据量较小，可打表
1 #include <cstdio>
2 #include <algorithm>
3 #include <cstring>
4 #include <cmath>
5 #include <string>
6 #include <iostream>
7 #include <vector>
8 #include <list>
9 #include <stack>
10 using namespace std;
11
12 #define REP(n) for(int o=0;o<n;o++)
13
14 int ans[] = {0,0,1,2,2,3,4,5,6,6,7,8,9,10,11,12,12,13,14,15,16,17,18,19,20,20,
15 21,22,23,24,25,26,27,28,29,30,30,31,32,33,34,35,36,37,38,39,40,41,42,42,43,
16 44,45,46,47,48,49,50,51,52,53,54,55,56,56,57,58,59,60,61,62,63,64,65,66,67,
17 68,69,70,71,72,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,90,
18 91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,110,
19 111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,
20 130,131,132,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,
21 148,149,150,151,152,153,154,155,156,156,157,158,159,160,161,162,163,164,165,
22 166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,182,183,
23 184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,
24 203,204,205,206,207,208,209,210,210,211,212,213,214,215,216,217,218,219,220,
25 221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,
26 240,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,
27 258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,272,273,274,275,
28 276,277,278,279,280,281,282,283,284,285,286,287,288,289,290,291,292,293,294,
29 295,296,297,298,299,300,301,302,303,304,305,306,306,307,308,309,310,311,312,
30 313,314,315,316,317,318,319,320,321,322,323,324,325,326,327,328,329,330,331,
31 332,333,334,335,336,337,338,339,340,341,342,342,343,344,345,346,347,348,349,
32 350,351,352,353,354,355,356,357,358,359,360,361,362,363,364,365,366,367,368,
33 369,370,371,372,373,374,375,376,377,378,379,380,380,381,382,383,384,385,386,
34 387,388,389,390,391,392,393,394,395,396,397,398,399,400,401,402,403,404,405,
35 406,407,408,409,410,411,412,413,414,415,416,417,418,419,420,420,421,422,423,
36 424,425,426,427,428,429,430,431,432,433,434,435,436,437,438,439,440,441,442,
37 443,444,445,446,447,448,449,450,451,452,453,454,455,456,457,458,459,460,461,
38 462,462,463,464,465,466,467,468,469,470,471,472,473,474,475,476,477,478,479,
39 480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,
40 499,500,501,502,503,504,505,506,506,507,508,509,510,511,512,513,514,515,516,
41 517,518,519,520,521,522,523,524,525,526,527,528,529,530,531,532,533,534,535,
42 536,537,538,539,540,541,542,543,544,545,546,547,548,549,550,551,552,552,553,
43 554,555,556,557,558,559,560,561,562,563,564,565,566,567,568,569,570,571,572,
44 573,574,575,576,577,578,579,580,581,582,583,584,585,586,587,588,589,590,591,
45 592,593,594,595,596,597,598,599,600,600,601,602,603,604,605,606,607,608,609,
46 610,611,612,613,614,615,616,617,618,619,620,621,622,623,624,625,626,627,628,
47 629,630,631,632,633,634,635,636,637,638,639,640,641,642,643,644,645,646,647,
48 648,649,650,650,651,652,653,654,655,656,657,658,659,660,661,662,663,664,665,
49 666,667,668,669,670,671,672,673,674,675,676,677,678,679,680,681,682,683,684,
50 685,686,687,688,689,690,691,692,693,694,695,696,697,698,699,700,701,702,702,
51 703,704,705,706,707,708,709,710,711,712,713,714,715,716,717,718,719,720,721,
52 722,723,724,725,726,727,728,729,730,731,732,733,734,735,736,737,738,739,740,
53 741,742,743,744,745,746,747,748,749,750,751,752,753,754,755,756,756,757,758,
54 759,760,761,762,763,764,765,766,767,768,769,770,771,772,773,774,775,776,777,
55 778,779,780,781,782,783,784,785,786,787,788,789,790,791,792,793,794,795,796,
56 797,798,799,800,801,802,803,804,805,806,807,808,809,810,811,812,812,813,814,
57 815,816,817,818,819,820,821,822,823,824,825,826,827,828,829,830,831,832,833,
58 834,835,836,837,838,839,840,841,842,843,844,845,846,847,848,849,850,851,852,
59 853,854,855,856,857,858,859,860,861,862,863,864,865,866,867,868,869,870,870,
60 871,872,873,874,875,876,877,878,879,880,881,882,883,884,885,886,887,888,889,
61 890,891,892,893,894,895,896,897,898,899,900,901,902,903,904,905,906,907,908,
62 909,910,911,912,913,914,915,916,917,918,919,920,921,922,923,924,925,926,927,
63 928,929,930,930,931,932,933,934,935,936,937,938,939,940,941,942,943,944,945,
64 946,947,948,949,950,951,952,953,954,955,956,957,958,959,960,961,962,963,964,
65 965,966,967,968,969,970,971,972,973,974};
66
67 int a(int N) {
68 bool light[1010] = {0};
69 for(int i = 1;i <= N;i++)
70 for(int j = i;j <= N;j += i)
71 light[j] = !light[j];
72 int cnt = 0;
73 REP(N) {
74 if(!light[o + 1])
75 cnt++;
76 }
77 return cnt;
78 }
79
80 int main() {
81 int N;
82 while(scanf("%d",&N) != EOF)
83 printf("%d\n",ans[N]);
84 return 0;
85 }
时间： 2025-01-02 09:06:15