One of the Dfs getting Started

The implementation of depth-first search is simple, and two factors need to be controlled:

1. Elements that have already been accessed are no longer accessible, and the elements that are inaccessible are added to the actual topic (barriers)

2. Cross-border This situation is not allowed

Take the 1312 Red and Black as an example, this is a typical DFS topic

Portal: http://acm.hdu.edu.cn/showproblem.php?pid=1312

The main idea: ' @ ' stands for the starting position, '. ' Represents the black point (which can be traversed), ' # ' represents the red dot (barrier) requires statistics to cover up to how many black dots

Topic Analysis: Determine starting position, start DFS, if not illegal location, count once, recursive search four directions (up, down, left, right)-end

Attach My code (for reference only):

#include <cstdio>#include<cstring>Const intMAXN = -+Ten;CharA[MAXN][MAXN];intW, H, IDX[MAXN][MAXN], CNT;intDfsintRintCintID) {    if(R <0|| R >= H | | C <0|| C >= W)return 0; if(Idx[r][c] >0|| A[R][C] = ='#')return 0; IDX[R][C]=ID; CNT++;  for(inti =-1; I <=1; i++)         for(intj =-1; J <=1; J + +)            if((i = =0&& J! =0)|| (I! =0&& J = =0)) Dfs (R+i, c+j, id);}intMain () {intR, C;  while(~SCANF ("%d%d", &w, &h)) {CNT=0; if(W = =0&& h = =0) Break;  for(inti =0; I < H; i++) scanf ("%s", A[i]); memset (IDX,0,sizeof(IDX));  for(inti =0; I < H; i++)             for(intj =0; J < W; J + +)                if(A[i][j] = ='@') {R=i; C=J; } DFS (R, C,1); printf ("%d\n", CNT); }    return 0;}

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One of the Dfs getting Started