基础训练 回形取数

回形取数

/*逆时针读数，但每读过一个就标志已读*/
#include<iostream>
#include<vector>
using namespace std;
int main(){
	int m, n, cnt=1, x=0, y=0, flag=0;
	cin>>m>>n;
	vector<vector<int> > M(m, vector<int>(n, 0)), visited(m, vector<int>(n,0));
	for(int i=0; i<m; i++)
		for(int j=0; j<n; j++)
			cin>>M[i][j];
		cout<<M[0][0]; visited[0][0]=1;
	while(cnt<m*n){
		while(x+1<m&&!visited[x+1][y]){
			visited[++x][y]=1; cnt++; 
			cout<<" "<<M[x][y]; 
		}
		while(y+1<n&&!visited[x][y+1]){
			visited[x][++y]=1; cnt++;
			cout<<" "<<M[x][y];
		}
		while(x-1>=0&&!visited[x-1][y]){
			visited[--x][y]=1; cnt++;
			cout<<" "<<M[x][y];
		}
		while(y-1>=0&&!visited[x][y-1]){
			visited[x][--y]=1; cnt++;
			cout<<" "<<M[x][y];
		}
	}
	cout<<endl;
	return 0;
}