2019icpc徐州区域赛F

F. The Answer to the Ultimate Question of Life, The Universe, and Everything.

 

我的第一道真·打表题

这次是真的打表啊，不是初始化求值！

重现赛的时候，一直在搞在线的做法，map和unordered_map都上了，都是TLE，初始化建立两个map，然后枚举a，b再找是否有c，我算的复杂度也就  O(T*5000*10000/2)?  2e8?好像确实得T。实际复杂度或许更高 ？

unordered_map内部哈希表实现，应该可以O(1)查找呀我感觉。stl的好用归好用，复杂度还是不太清楚。

 

打表的方法也是刚学的，对每个x，枚举a，b，二分找c   。 反正最好就是按一定格式打表出来，直接复制存到一个数组交上去就行了。

 

枚举的时候注意，三个数中至少有一个非负数，a可以在0~5000，应该能少一半的时间，也许？反正能优化就上吧。

 

打表的适用范围：对每个输入的数据，答案固定可知，且输入的数据范围较小。数据范围较小是重点，这里要整个更大的数x，一场比赛都打不完表。

 

  1 #include 
  2 #define debug(x) cout << #x << ": " << x << endl
  3 using namespace std;
  4 typedef long long ll;
  5 const int MAXN=2e5+7;
  6 const int INF=0x3f3f3f3f;
  7 const int MOD=1e9+7;
  8 
  9 
 10 int ans[][3]=
 11 {
 12 -5000,0,5000,
 13 -5000,1,5000,
 14 -4373,-486,4375,
 15 -5,4,4,
 16 11111,0,0,
 17 11111,0,0,
 18 -637,-205,644,
 19 -169,44,168,
 20 -5000,2,5000,
 21 -216,-52,217,
 22 -650,-353,683,
 23 -695,-641,843,
 24 -11,7,10,
 25 11111,0,0,
 26 11111,0,0,
 27 -265,-262,332,
 28 -4114,-588,4118,
 29 -3331,2195,2977,
 30 -1373,-1276,1671,
 31 -95,47,91,
 32 -2816,-741,2833,
 33 -401,-287,445,
 34 11111,0,0,
 35 11111,0,0,
 36 -10,8,8,
 37 -2683,1839,2357,
 38 -2107,237,2106,
 39 -5000,3,5000,
 40 -2268,-249,2269,
 41 -233,-69,235,
 42 11111,0,0,
 43 11111,0,0,
 44 11111,0,0,
 45 11111,0,0,
 46 -1555,-244,1557,
 47 -1120,-509,1154,
 48 -3223,2358,2731,
 49 -444,-84,445,
 50 -27,16,25,
 51 11111,0,0,
 52 11111,0,0,
 53 11111,0,0,
 54 11111,0,0,
 55 -823,-307,837,
 56 -7,-5,8,
 57 -2369,1709,2025,
 58 -758,-473,815,
 59 -141,49,139,
 60 -3950,-1247,3991,
 61 11111,0,0,
 62 11111,0,0,
 63 -796,602,659,
 64 11111,0,0,
 65 -2370,1518,2141,
 66 -3885,-648,3891,
 67 -3329,1837,3131,
 68 -672,505,559,
 69 -998,361,982,
 70 11111,0,0,
 71 11111,0,0,
 72 -1201,-163,1202,
 73 -966,668,845,
 74 -2744,-1561,2903,
 75 -161,102,146,
 76 -5000,4,5000,
 77 -929,403,903,
 78 1,1,4,
 79 11111,0,0,
 80 11111,0,0,
 81 -403,134,398,
 82 -2359,824,2325,
 83 -533,401,443,
 84 -432,-104,434,
 85 -335,-146,344,
 86 11111,0,0,
 87 11111,0,0,
 88 11111,0,0,
 89 11111,0,0,
 90 -2080,-829,2123,
 91 -706,-196,711,
 92 -1300,-706,1366,
 93 -2368,-1719,2638,
 94 -1317,847,1188,
 95 -3707,1315,3651,
 96 11111,0,0,
 97 11111,0,0,
 98 11111,0,0,
 99 -4126,-1972,4271,
100 -1390,-1282,1686,
101 -2514,1953,2036,
102 -1803,365,1798,
103 -3389,-2912,3992,
104 -4052,861,4039,
105 -248,-98,253,
106 11111,0,0,
107 11111,0,0,
108 -22,14,20,
109 -3168,-991,3200,
110 -2101,-1638,2391,
111 -893,-622,984,
112 -1797,-903,1870,
113 -2327,319,2325,
114 -239,118,229,
115 11111,0,0,
116 11111,0,0,
117 -7,-4,8,
118 -2689,-1165,2760,
119 -1309,947,1117,
120 -1165,-948,1345,
121 -2948,853,2924,
122 11111,0,0,
123 -4793,-2312,4966,
124 11111,0,0,
125 11111,0,0,
126 11111,0,0,
127 -12,8,11,
128 -1906,-757,1945,
129 -896,-555,962,
130 -4328,383,4327,
131 -3677,-1673,3789,
132 -2804,1219,2725,
133 11111,0,0,
134 11111,0,0,
135 -37,-16,38,
136 -1,0,5,
137 -5000,5,5000,
138 -2212,-419,2217,
139 -4034,-3881,4988,
140 -3989,-726,3997,
141 -1580,-1238,1801,
142 11111,0,0,
143 11111,0,0,
144 -1,2,5,
145 -399,167,389,
146 -3013,-1766,3203,
147 -1351,-629,1395,
148 -1116,816,946,
149 -758,-428,801,
150 -86,-77,103,
151 11111,0,0,
152 11111,0,0,
153 -139,104,116,
154 -7,-3,8,
155 11111,0,0,
156 -2746,-2552,3342,
157 -8,-7,10,
158 -327,-263,376,
159 -2366,1528,2131,
160 11111,0,0,
161 11111,0,0,
162 -367,260,317,
163 -463,215,447,
164 -805,486,741,
165 -3736,-695,3744,
166 -2135,-516,2145,
167 -3693,-1049,3721,
168 11111,0,0,
169 11111,0,0,
170 11111,0,0,
171 -1534,383,1526,
172 -3874,-1654,3972,
173 -4767,-2476,4980,
174 -4125,-1417,4180,
175 -3423,-2943,4033,
176 -66,-59,79,
177 11111,0,0,
178 11111,0,0,
179 11111,0,0,
180 -802,-574,890,
181 -1354,-1012,1521,
182 -3834,-2149,4047,
183 -1328,891,1178,
184 11111,0,0,
185 11111,0,0,
186 -335,-170,349,
187 11111,0,0,
188 11111,0,0,
189 -1168,-160,1169,
190 -13,-10,15,
191 -2839,1503,2691,
192 11111,0,0,
193 -4874,974,4861,
194 -90,-29,91,
195 -4889,976,4876,
196 11111,0,0,
197 11111,0,0,
198 -4,5,5,
199 -1885,-1092,2000,
200 -1639,318,1635,
201 -1702,-1403,1974,
202 -4812,-593,4815,
203 -377,-215,399,
204 -20,16,16,
205 11111,0,0,
206 11111,0,0,
207 11111,0,0,
208 -1057,-579,1112,
209 -2867,-1606,3026,
210 -3752,-1347,3809,
211 -2208,508,2199,
212 -2318,-638,2334,
213 };
214 
215 ll qq[210][3];
216 
217 
218 ll check(ll t)
219 {
220     ll l=-5000,r=5000,res=INF;
221     while(l<=r)
222     {
223         ll mid=l+r>>1;
224         ll tmp=mid*mid*mid;
225         if(tmp==t) return mid;
226         if(tmp>t) r=mid-1;
227         else l=mid+1;
228     }
229     return res;
230 }
231 
232 int main()
233 {
234     int t;
235     //init();
236 
237    /* for(ll x=0;x<=200;++x)
238     {
239         ll c=INF;
240         for(ll i=-5000;i<=5000;++i)
241         {
242             for(ll j=-5000;j<=5000;++j)
243             {
244                 ll t=x-i*i*i-j*j*j;
245                 c=check(t);
246                 if( abs(c)<=5000)
247                 {
248                     printf("%lld,%lld,%lld,\n",i,j,c);
249                     break;
250                 }
251             }
252             if( abs(c)<=5000) break;
253         }
254         if( abs(c)<=5000) continue;
255         else printf("11111,0,0,\n");
256     }*/
257     cin>>t;
258     while(t--)
259     {
260         int x;
261         cin>>x;
262         if(ans[x][0]==11111) cout<<"impossible"<<endl;
263         else cout<0]<<' '<1]<<' '<2]<<endl;
264     }
265     return 0;
266 }