[HIHO1184]连通性二·边的双连通分量（双连通分量）-白红宇

[HIHO1184]连通性二·边的双连通分量（双连通分量）

阅读量：5338 次

发布时间：2019-06-15

本文共 3443 字，大约阅读时间需要 11 分钟。

题目链接：http://hihocoder.com/problemset/problem/1184

题意裸，写个博客记下输出姿势。

1 /*  2 ━━━━━┒ギリギリ♂ eye！  3 ┓┏┓┏┓┃キリキリ♂ mind！  4 ┛┗┛┗┛┃＼○／  5 ┓┏┓┏┓┃ /  6 ┛┗┛┗┛┃ノ)  7 ┓┏┓┏┓┃  8 ┛┗┛┗┛┃  9 ┓┏┓┏┓┃ 10 ┛┗┛┗┛┃ 11 ┓┏┓┏┓┃ 12 ┛┗┛┗┛┃ 13 ┓┏┓┏┓┃ 14 ┃┃┃┃┃┃ 15 ┻┻┻┻┻┻ 16 */ 17 #include 
     
       18 #include 
      
        19 #include 
       
         20 #include 
        
          21 #include 
         
           22 #include 
          
            23 #include 
           
             24 #include 
            
              25 #include 
             
               26 #include 
              
                27 #include 
               
                 28 #include 
                
                  29 #include 
                 
                   30 #include 
                  
                    31 #include 
                   
                     32 #include 
                    
                      33 #include 
                      34 #include 
                      
                        35 using namespace std; 36 #define fr first 37 #define sc second 38 #define cl clear 39 #define BUG puts("here!!!") 40 #define W(a) while(a--) 41 #define pb(a) push_back(a) 42 #define Rint(a) scanf("%d", &a) 43 #define Rll(a) scanf("%lld", &a) 44 #define Rs(a) scanf("%s", a) 45 #define Cin(a) cin >> a 46 #define FRead() freopen("in", "r", stdin) 47 #define FWrite() freopen("out", "w", stdout) 48 #define Rep(i, len) for(int i = 0; i < (len); i++) 49 #define For(i, a, len) for(int i = (a); i < (len); i++) 50 #define Cls(a) memset((a), 0, sizeof(a)) 51 #define Clr(a, x) memset((a), (x), sizeof(a)) 52 #define Full(a) memset((a), 0x7f7f, sizeof(a)) 53 #define lrt rt << 1 54 #define rrt rt << 1 | 1 55 #define pi 3.14159265359 56 #define RT return 57 #define lowbit(x) x & (-x) 58 #define onenum(x) __builtin_popcount(x) 59 typedef long long LL; 60 typedef long double LD; 61 typedef unsigned long long ULL; 62 typedef pair
                       
                         pii; 63 typedef pair
                        
                          psi; 64 typedef pair
                         
                           pll; 65 typedef map
                          
                            msi; 66 typedef vector
                           
                             vi; 67 typedef vector
                            
                              vl; 68 typedef vector
                             
                               vvl; 69 typedef vector
                              
                                vb; 70 71 const int maxn = 50020; 72 const int maxm = 500100; 73 typedef struct Edge { 74 int u, v; 75 int next, i; 76 bool cut; 77 Edge() {} 78 Edge(int uu, int vv, int ii) : u(uu), v(vv), i(ii) {} 79 }Edge; 80 81 Edge edge[maxm]; 82 int head[maxn], ecnt; 83 int n, m; 84 int dfn[maxn]; 85 int low[maxn]; 86 bool vis[maxn]; 87 bool cut[maxn]; 88 vi bridge; 89 int st[maxn], top; 90 int belong[maxn], bcnt; 91 vi tmp; 92 int ret; 93 94 void init() { 95 Clr(head, -1); Cls(low); Cls(dfn); 96 Cls(vis); Cls(cut); Cls(st); ret = 0; 97 bcnt = 1; top = 0; ecnt = 0; bridge.cl(); 98 } 99 100 void adde(int uu, int vv, int ii) {101 edge[ecnt] = Edge(uu, vv, ii);102 edge[ecnt].cut = 0;103 edge[ecnt].next = head[uu];104 head[uu] = ecnt++;105 }106 107 108 void tarjan(int u, int d, int p) {109 low[u] = dfn[u] = d;110 st[++top] = u;111 vis[u] = 1;112 for(int i = head[u]; ~i; i=edge[i].next) {113 int v = edge[i].v;114 int id = edge[i].i;115 if(p == id) continue;116 if(!dfn[v]) {117 tarjan(v, d+1, id);118 low[u] = min(low[u], low[v]);119 if(low[v] > dfn[u]) {120 bridge.pb(i);121 edge[i].cut = edge[i^1].cut = 1;122 }123 }124 else low[u] = min(low[u], dfn[v]);125 }126 if(low[u] == dfn[u]) {127 tmp.cl();128 int v;129 bcnt = 0x7f7f7f;130 do {131 v = st[top--];132 vis[v] = 0;133 bcnt = min(bcnt, v);134 tmp.pb(v);135 }while(v != u);136 Rep(i, tmp.size()) belong[tmp[i]] = bcnt;137 ret++;138 }139 }140 141 int main() {142 // FRead();143 int u, v;144 while(~scanf("%d%d", &n, &m)) {145 init();146 For(i, 1, m+1) {147 Rint(u); Rint(v);148 adde(u, v, i);149 adde(v, u, i);150 }151 For(i, 1, n+1) {152 if(!dfn[i]) tarjan(i, 1, -1);153 }154 printf("%d\n", ret);155 For(i, 1, n+1) printf("%d ", belong[i]);156 printf("\n");157 }158 RT 0;159 }