1105 Spiral Matrix

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

知识点：简单模拟；vector的使用
思路： 
矩阵应该利用vector的数组来构建；因为如果是形成比较方正的矩阵，长和宽最大是100左右；但如果是质数，矩阵就会变成长条形长在10000以内，这样利用普通二维数组数组会超限；利用了vector容器可以.resize()的特点。
单列的输出特殊处理

#include <iostream>
#include <string>
#include <algorithm>
#include <cmath>
#include <vector>
using namespace std;
const int maxn = 1000;

vector<int> matrix[maxn];

bool cmp(int a,int b){
    return a>b;
}

int getLong(int n){
    int i;
    for(i=sqrt(n)+0.9;i<=n && n%i!=0;i++);
    return i;
}

int main(){
    vector<int> list;
    int n,tmp; cin >> n;
    for(int i=0;i<n;i++){
        scanf("%d",&tmp);
        list.push_back(tmp);
    }
    sort(list.begin(), list.end(), cmp);
    int l = getLong(n);
    int w = n/l;
    for(int i=1;i<=l;i++){
        matrix[i].resize(w+1);
    }
    int x=1, y=1, ptr=0;

    int base=0;
    while(ptr<list.size()){
        if(w==1){
            for(;y<=l+base;y++){
                matrix[y][x]=list[ptr++];
            }
            break;
        }
        for(; x<=w+base; x++){
            
            matrix[y][x]=list[ptr++];
        }
        
        x--; y++;
        for(; y<l+base; y++){
            matrix[y][x]=list[ptr++];
        }        
        for(; x>=1+base; x--){
            matrix[y][x]=list[ptr++];
        }
        x++; y--;
        for(; y>1+base; y--){
            matrix[y][x]=list[ptr++];
        }
        x++; y++;
        w-=2; l-=2;
        base++;
        //printf("%d %d w=%d l=%d",x,y,w,l);
        
    }
    for(int i=1;i<=getLong(n);i++){
        for(int j=1;j<=(n/getLong(n));j++){
            if(j!=1) printf(" ");
            printf("%d",matrix[i][j]);
        }
        printf("
");
    }
}