Acwing Brush Questions Section 1

756

Topic Analysis:

The key points are as follows:

1. Matrix traversal: determine the traversal direction

2. Determine the traversal boundary

#include #include #include using namespace std;const int N = 110;int n,m;int res[N][N];int main(){cin>>n>>m;int dx[] = {0,1,0,-1};int dy[] = {1,0,-1,0};for(int x = 0,y = 0 ,k = 1,d = 0;k<=n*m;k++){res[x][y] = k;int a = x+dx[d],b = y + dy[d];if(a<0 || a>=n ||b<0||b>=m||res[a][b]){d = (d+1)%4;a = x + dx[d], b = y + dy[d];}x = a,y = b;}for(int i = 0;i