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Hdu1824: http://acm.hdu.edu.cn/showproblem.php? PID = 1, 1824

Question: Chinese.

Question: two constraints must be considered when this question is created. One is internal to the team, that is, if a, B, c, a --> ~ B, B --> ~ A; A --> ~ C, C --> ~ A; at the same time, B and C must be left at the same time, so B --> C, C --> B ;~ B --> ~ C ,~ C --> ~ B; that is, B needs to stay C, C needs to stay B, B does not stay C, C does not stay B does not need to stay;, and then the situation of each pair, you can directly create an edge.

1 # include <iostream> 2 # include <cstdio> 3 # include <cstring> 4 # include <algorithm> 5 using namespace STD; 6 int T, M, N; 7 const int n = 200010; 8 const int M = 400010; 9 const int INF = 0 xffffffff; 10 struct edge {11 int to, next; 12} edge [m]; 13 int CNT, U, V, DEP, top, Atype; 14 int dfn [N], low [N], vis [N], head [N], st [N], belong [N], in [N], out [N], sum [N]; 15 // sum [I] records the number of vertices in the I-connected graph. In [I], out [I] indicates the inbound and initial degrees of the vertex after the contraction. 16 void Init () {17 CNT = Dep = Top = Atype = 0; 18 memset (Head,-1, sizeof (head); 19 memset (dfn, 0, sizeof (dfn); 20 memset (low, 0, sizeof (low); 21 memset (VIS, 0, sizeof (VIS); 22 memset (belong, 0, sizeof (belong); 23 memset (in, 0, sizeof (in); 24 memset (Out, 0, sizeof (out); 25 memset (sum, 0, sizeof (SUM); 26} 27 void addedge (int u, int v) {28 edge [CNT]. to = V; 29 edge [CNT]. next = head [u]; 30 head [u] = CNT ++; 31} 32 33 void Tarjan (int u) {3 4 dfn [u] = low [u] = ++ Dep; 35 st [top ++] = u; 36 vis [u] = 1; 37 For (INT I = head [u]; I! =-1; I = edge [I]. Next) {38 int v = edge [I]. To; 39 if (! Dfn [v]) {40 Tarjan (V); 41 low [u] = min (low [u], low [v]); 42} 43 else if (vis [v]) {44 Low [u] = min (low [u], dfn [v]); 45} 46} 47 Int J; 48 if (dfn [u] = low [u]) {49 Atype ++; 50 do {51 J = sT [-- top]; 52 belong [J] = Atype; 53 sum [Atype] ++; // records the number of the midpoint of each connected component 54 vis [J] = 0; 55} 56 while (u! = J); 57} 58} 59 int FG [N], T1, T2, T3; 60 int main () {61 while (~ Scanf ("% d", & T, & M) {62 int A, B, C; 63 int base = 3 * t; 64 Init (); 65 for (INT I = 0; I <t; I ++) {66 scanf ("% d", & A, & B, & C ); 67 addedge (B, c); 68 addedge (C, B); 69 addedge (B + base, C + base); 70 addedge (C + base, B + base ); 71 addedge (a + base, B); 72 addedge (a + base, c); 73 addedge (B + base, a); 74 addedge (C + base, ); 75} 76 while (M --) {77 scanf ("% d", & A, & B); 78 addedge (A, B + base ); 79 addedge (B, A + base); 80} 81 For (INT I = 0; I <6 * t; I ++) 82 If (! Dfn [I]) 83 Tarjan (I); 84 bool flag = false; 85 for (INT I = 1; I <3 * t; I ++) {86 If (belong [I] = belong [I + base]) {87 flag = true; 88 break; 89} 90} 91 If (! Flag) printf ("Yes \ n"); 92 else93 printf ("NO \ n"); 94} 95 96}

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