Hdoj 3018 Ant Trip (non-Tuola Road | | One stroke + and check set)

title Link:http://acm.hdu.edu.cn/showproblem.php?pid=3018

Thinking Analysis: The title can be seen as a stroke of the problem, the minimum number of strokes can be painted all the edges and draw only once;

First, the number of connected graphs in the undirected graph can be obtained, and the number of strokes to be drawn in each undirected graph is calculated and added. In an undirected connected graph, if all points have an even number, there is a Euler loop,

You only need to draw a pen, if you have an odd-numbered point, you need to draw a number of points with an odd degree of number/2; The isolated points needing attention do not need to be drawn;

The code is as follows:

#include <cstdio>#include<cstring>#include<iostream>using namespacestd;Const intMax_n =100000+ -;intFa[max_n], odd[max_n];intLink[max_n], set_count[max_n];voidInit () { for(inti =0; i < max_n; ++i) {Set_count[i]=1; Fa[i]=i; }}intFind (intnum) {    if(Fa[num] = =num)returnnum; Else        returnFa[num] =Find (Fa[num]);}intUnion (intAintb) {    intFa_a =Find (a); intFa_b =Find (b); if(Fa_a = =fa_b)return-1; Else if(Fa_a >fa_b) {Fa[fa_b]=fa_a; SET_COUNT[FA_A]+=Set_count[fa_b]; }    Else{fa[fa_a]=Fa_b; Set_count[fa_b]+=Set_count[fa_a]; }    return 1;}intMain () {intVertex_num, Road_num; intver_1, ver_2;  while(SCANF ("%d%d", &vertex_num, &road_num)! =EOF) {        intAns =0;        Init (); memset (Link,0,sizeof(link)); memset (Odd,0,sizeof(odd));  for(inti =0; i < Road_num; ++i) {scanf ("%d%d", &ver_1, &ver_2); Link[ver_1]++; Link[ver_2]++;        Union (ver_1, ver_2); }         for(inti =1; I <= vertex_num; ++i) {intFA =Find (i); if((link[i) &1) ==1) ODD[FA]++; }         for(inti =1; I <= vertex_num; ++i) {if(Fa[i] = = i && set_count[i]! =1)            {                if(Odd[i] = =0) ans++; Elseans+ = Odd[i]/2; }} printf ("%d\n", ans); }    return 0;}

Hdoj 3018 Ant Trip (non-Tuola Road | | One stroke + and check set)