2045：【例5.13】蛇形填数

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    int a[n][n],i=0,j=n-1,t=1;
    memset(a,0,sizeof(a));
    a[i][j]=1;
    while(t!=n*n){
        while(a[i+1][j]==0&&i+1<n){
            a[++i][j]=++t;
        }
        while(a[i][j-1]==0&&j-1>=0){
            a[i][--j]=++t;
        }
        while(a[i-1][j]==0&&i-1>=0){
            a[--i][j]=++t;
        }
        while(a[i][j+1]==0&&j+1<n){
            a[i][++j]=++t;
        }
    }
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            cout<<a[i][j]<<" ";
        }
        cout<<endl;
    }
}

 

#include <iostream>
using namespace std;
int main(){
    int n;
    int f=0;
    int i=1;
    cin>>n;
    int x=n,y=1;
    int a[n+1][n+1]={0};
    while(i!=n*n+1){    
        a[y][x]=i;
        if(f==0){//下↓ 
            y+=1;
        }else if(f==1){//← 
            x-=1;
        }else if(f==2){//↑ 
            y-=1;
        }else if(f==3){//→ 
            x+=1;
        } 
        if(((x==n && y==n) || (x==1 && y==n) || (x==1 && y==1) || (x==n && y==1))){
            f++;
            f%=4;
        }else if((f==0 && a[y+1][x]!=0) || (f==1 && a[y][x-1]!=0) || (f==2 && a[y-1][x]!=0) || (f==3 && a[y][x+1]!=0)){
            f++;
            f%=4;
        }
        i++;
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cout<<a[i][j]<<" ";
        }
        cout<<endl;
    }
    return 0;
    
}