题目描述

1105 Spiral Matrix (25分)

This time your job is to fill a sequence of N positive integers into a spiral matrix in non-increasing order. A spiral matrix is filled in from the first element at the upper-left corner, then move in a clockwise spiral. The matrix has m rows and n columns, where m and n satisfy the following: m×n must be equal to N; m≥n; and m−n is the minimum of all the possible values.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N. Then the next line contains N positive integers to be filled into the spiral matrix. All the numbers are no more than 10​4​​. The numbers in a line are separated by spaces.
Output Specification:

For each test case, output the resulting matrix in m lines, each contains n numbers. There must be exactly 1 space between two adjacent numbers, and no extra space at the end of each line.
Sample Input:

12
37 76 20 98 76 42 53 95 60 81 58 93

Sample Output:

98 95 93
42 37 81
53 20 76
58 60 76

#include<iostream>
#include<cstring>
#include<algorithm>
#include<vector>

using namespace std;

const int N=10010;

int n;
int w[N];

int main()
{
    cin>>n;
    for(int i=0;i<n;i++) cin>>w[i];

    sort(w,w+n,greater<int>());

    int r,c;
    for(int i=1;i<=n/i;i++)
        if(n%i==0)
        {
            r=n/i;
            c=i;
         } 

    vector<vector<int>> res(r,vector<int>(c));

    int dx[]={-1,0,1,0},dy[4]={0,1,0,-1};
    for(int i=0,x=0,y=0,d=1;i<n;i++)
    {
        res[x][y]=w[i];
        int a=x+dx[d],b=y+dy[d];
        if(a<0||a>=r||b<0||b>=c||res[a][b])
        {
            d=(d+1)%4;
            a=x+dx[d],b=y+dy[d];
        }
        x=a,y=b;
    }

    for(int i=0;i<r;i++)
    {
        cout<<res[i][0];
        for(int j=1;j<c;j++)
            cout<<' '<<res[i][j];
        cout<<endl; 
    }
    return 0;
}