UVA 796-critical Links "Finding Bridges"

link:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&itemid=8&page=show_problem& problem=737

Test instructions
To find the number and edge of the bridge, the order of the points of the output edge is from small to large

Code:

#include <stdio.h>#include <ctime>#include <math.h>#include <limits.h>#include <complex>#include <string>#include <functional>#include <iterator>#include <algorithm>#include <vector>#include <stack>#include <queue>#include <set>#include <map>#include <list>#include <bitset>#include <sstream>#include <iomanip>#include <fstream>#include <iostream>#include <ctime>#include <cmath>#include <cstring>#include <cstdio>#include <time.h>#include <ctype.h>#include <string.h>#include <assert.h>#pragma COMMENT (linker, "/stack:102400000,102400000")using namespace STD;intN, m, x, y;Const intMAXN =1001000;Const intMAXM =1000100;intNumChartmp vector<pair<int, int>> A;structedge{intTo, next;BOOLCut//Is the mark of the bridge}EDGE[MAXM];intHEAD[MAXN], tot;intLOW[MAXN], DFN[MAXN], STACK[MAXN];intIndex, top;BOOLINSTACK[MAXN];BOOLCUT[MAXN];intADD_BLOCK[MAXN];//Delete a point after adding the connected blockintBridgevoidAddedge (intUintV) {edge[tot].to = v; edge[tot].next = head[u]; edge[tot].cut =false; Head[u] = tot++;}voidTarjan (intUintPre) {intV    Low[u] = dfn[u] = ++index;    stack[top++] = u; Instack[u] =true;intson =0; for(inti = Head[u]; I! =-1; i = edge[i].next) {v = edge[i].to;if(v = = Pre)Continue;if(!            Dfn[v]) {son++; Tarjan (V, u);if(Low[u] > Low[v]) Low[u] = Low[v];//Bridge            ( u,v) is a bridge when and only if (U,V) is a branch edge and satisfies the DFS (u) <low (v).             if(Low[v] > Dfn[u])                {bridge++; Edge[i].cut =true; Edge[i ^1].cut =true;            A.push_back (Make_pair (min (U, v), max (U, v))); }//Cutting point            //a vertex u is a cut point, when and only if satisfies (1) or (2) (1) U is a root, and U has more than one subtree.             //(2) U is not a root, and satisfies the presence (U,V) as a branch edge (or parent-child side,            //That is, U is the father of V in the search tree, so dfs (u) <=low (v)            if(U! = Pre && low[v] >= Dfn[u])//Not root{Cut[u] =true;            add_block[u]++; }        }Else if(Low[u] > Dfn[v])    Low[u] = Dfn[v]; }//root, number of branches greater than 1    if(U = = Pre && son >1) Cut[u] =true;if(U = = pre) Add_block[u] = son-1; Instack[u] =false; top--;}voidSolveintN) {memset(DFN,0,sizeof(DFN));memset(Instack,false,sizeof(Instack));memset(Add_block,0,sizeof(Add_block));memset(Cut,false,sizeof(cut)); Index = top =0; Bridge =0; for(inti =1; I <= N; i++)if(!    Dfn[i]) Tarjan (i, I); Sort (A.begin (), A.end ());printf("%d critical links\n", bridge); for(inti =0; I < a.size (); i++)printf("%d-%d\n", A[i].first-1, A[i].second-1);printf("\ n");}voidInit () {tot =0; num =0; A.clear ();memset(Head,-1,sizeof(head));}intMain () { while(~scanf("%d", &n)) {init (); for(inti =1; I <= N; i++) {scanf("%d", &m); M + =1; GetChar ();scanf("%c", &tmp);scanf("%d", &x);scanf("%c", &tmp); while(x--) {scanf("%d", &y); Y + =1;                Addedge (M, y);            Addedge (Y, M);    }} solve (n); }return 0;}

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UVA 796-critical Links "Finding Bridges"