문제접근![](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==)
놓쳤던 부분![](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==)
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최단거리를 구하는 문제에서는 bfs가 더 효율적
dfs는 구해진 답이 최선이라는 보장이 없어서 다 돌아아하지만, bfs는 구해진 답이 항상 최소임이 보장됨
코드![](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==)
2208 KB
0 ms
#include <iostream>
#include <string>
#include <queue>
#include <utility>
using namespace std;
#define MAX 101
int dx[4] = {0, 1, 0, -1};
int dy[4] = {-1, 0, 1, 0};
bool visited[MAX][MAX];
int map[MAX][MAX];
int answer = 10001;
int n,m;
void bfs()
{
queue<pair<int,int>> q;
q.push({1, 1});
while(!q.empty())
{
int cur_row = q.front().first;
int cur_col = q.front().second;
q.pop();
for (int i = 0; i < 4; i++)
{
int next_row = cur_row + dy[i];
int next_col = cur_col + dx[i];
if (next_row <= 0 || next_row > n || next_col <= 0 || next_col > m || visited[next_row][next_col])
continue ;
if (map[next_row][next_col] == 0)
continue ;
visited[next_row][next_col] = true;
map[next_row][next_col] = map[cur_row][cur_col] + 1;
q.push({next_row, next_col});
}
}
}
int main(void)
{
string input;
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for (int i = 1; i <= n; i++)
{
cin >> input;
for (int j = 1; j <= m; j++)
map[i][j] = input[j - 1] - '0';
}
bfs();
cout << map[n][m];
return (0);
}
C++
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