Ultraviolet A 10596-morning walk, naked Euler's loop

10596-Morning Walk

3791

37.43%

1073

89.84%

Question link:

Http://uva.onlinejudge.org/index.php? Option = com_onlinejudge & Itemid = 8 & category = 105 & page = show_problem & problem = 1537

Question type: Euler loop, query set, DFS

Question:

Kamal isMotashotaGuy.
He has got a new job in Chittagong. So, he has moved to Chittagong from Dinajpur.
He was getting fatter in Dinajpur as he had no work in his hand there.
So, moving to Chittagong has turned to be a blessing for him. Every morning he takes a walk through the hilly roads of Charming City Chittagong.
He is enjoying this city very much. There are so many roads in chittagongand every morning he takes different paths for his walking. But while choosing a path he makes sure
He does not visit a road twice not even in his way back home. an intersection point of a road is not considered as the part of the road. in a sunny morning, he was thinking about how it wocould be if he cocould visit all the roads of the city in a single walk.
Your task is to help Kamal in determining whether it is possible
He or not.

Question:

Kamal goes from home to chittagongand every morning. There are many routes from home to chittagongand,
He needs to select a route every morning from home to chittagongand and go back to home from chittagongand. This route cannot go through the same route repeatedly. There may be multiple routes between two locations. For example, if the route from A to B appears multiple times, it means that each time it appears, it is a different path.

Analysis and Summary:

This is the naked Euler loop. Ultraviolet
10054-The neck.pdf and
Ultraviolet
10129-play on words. No longer cumbersome

1. Euler Loop + DFS

# Include <cstring> # include <iostream> # include <cstdio> using namespace STD; int vis [210], n, m, G [210] [210], indegree [210], outdegree [210]; void DFS (INT v) // depth-first traversal {vis [v] = true; For (INT I = 0; I <N; I ++) {If (! Vis [I] & G [v] [I]) {DFS (I) ;}} int main () {# ifdef local freopen ("input.txt ", "r", stdin); # endif while (~ Scanf ("% d", & N, & M) {memset (G, 0, sizeof (g); int A, B; memset (VIS, 0, sizeof (VIS); For (INT I = 0; I <m; ++ I) {scanf ("% d", & A, & B ); G [a] [B] = G [B] [a] = 1; ++ vis [a]; ++ vis [B];} int CNT = 0; for (INT I = 0; I <n; ++ I) {If (vis [I] % 2 = 1) {++ CNT; break ;}} memset (VIS, 0, sizeof (VIS); If (CNT | M <2) printf ("Not possible \ n"); else {DFS (0 ); bool flag = true; For (INT I = 0; I <n; ++ I) {If (! Vis [I]) Flag = false;} If (FLAG) printf ("Possible \ n"); else printf ("Not possible \ n") ;}} return 0 ;}

2. Euler Loop + and query set

# Include <cstring> # include <iostream> # include <cstdio> using namespace STD; int vis [210], n, m, G [210] [210], indegree [210], outdegree [210], F [210]; void Init () // check whether the set is a connected graph {int I; for (I = 0; I <n; I ++) f [I] = I;} int find (INT X) {int r = x; while (F [R]! = R) r = f [R]; F [x] = r; return r;} void Union (int x, int y) {int FX, FY; FX = find (x); FY = find (y); If (FX! = FY) f [FX] = FY;} int main () {# ifdef local freopen ("input.txt", "r", stdin); # endif while (~ Scanf ("% d", & N, & M) & N) {memset (G, 0, sizeof (g); int A, B; init (); memset (VIS, 0, sizeof (VIS); For (INT I = 0; I <m; ++ I) {scanf ("% d", & A, & B); ++ G [a] [B]; ++ G [B] [a]; ++ vis [a]; ++ vis [B]; Union (a, B);} int ans = 0; For (INT I = 0; I <N; ++ I) if (F [I] = I) ++ ans; If (ANS = 1 & M> = 2) {int CNT = 0; for (INT I = 0; I <n; ++ I) {If (vis [I] % 2 = 1) {++ CNT; break ;}} if (CNT) printf ("Not possible \ n"); else printf ("Possible \ n");} else printf ("Not possible \ n ");} return 0 ;}

-- The meaning of life is to give it meaning.
Original Http://blog.csdn.net/shuangde800 ,
D_double