数论/暴力 Codeforces Round #305 (Div. 2) C. Mike and Frog

 

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 1 /*  2  数论/暴力：找出第一次到a1,a2的次数，再找到完整周期p1,p2，然后以2*m为范围  3  t1,t2为各自起点开始“赛跑”，谁落后谁加一个周期，等到t1 == t2结束  4  详细解释：http://blog.csdn.net/u014357885/article/details/46044287  5 */  6 #include <cstdio>  7 #include <algorithm>  8 #include <cstring>  9 #include <iostream> 10 using namespace std; 11 12 typedef long long ll; 13 14 const int MAXN = 1e3 + 10; 15 const int INF = 0x3f3f3f3f; 16 17 int main(void) //Codeforces Round #305 (Div. 2) C. Mike and Frog 18 { 19 int m; 20  ll h1, a1, x1, y1, h2, a2, x2, y2; 21 while (scanf ("%d%I64d%I64d%I64d%I64d%I64d%I64d%I64d%I64d", &m, &h1, &a1, &x1, &y1, &h2, &a2, &x2, &y2) == 9) 22  { 23 ll t1 = -1, t2 = -1, p1 = -1, p2 = -1; 24 for (int i=1; i<=m; ++i) //get t1, p1 25  { 26 h1 = (h1 * x1 + y1) % m; 27 if (h1 == a1) {t1 = i; break;} 28  } 29 if (t1 == -1) {puts ("-1"); continue;} 30 for (int i=1; i<=m; ++i) 31  { 32 h1 = (h1 * x1 + y1) % m; 33 if (h1 == a1) {p1 = i; break;} 34  } 35 36 for (int i=1; i<=m; ++i) //get t2, p2 37  { 38 h2 = (h2 * x2 + y2) % m; 39 if (h2 == a2) {t2 = i; break;} 40  } 41 if (t2 == -1) {puts ("-1"); continue;} 42 for (int i=1; i<=m; ++i) 43  { 44 h2 = (h2 * x2 + y2) % m; 45 if (h2 == a2) {p2 = i; break;} 46  } 47 48 bool ok = false; //get t1 == t2 49 for (int i=1; i<=2*m; ++i) 50  { 51 if (t1 == t2) {ok = true; printf ("%I64d\n", t1); break;} 52 if (t1 < t2) t1 += p1; 53 else t2 += p2; 54  } 55 if (!ok) puts ("-1"); 56  } 57 58 return 0; 59 } 60 61 /* 62 5 63 4 2 64 1 1 65 0 1 66 2 3 67 1023 68 1 2 69 1 0 70 1 2 71 1 1 72 */