PAT 甲级 1105 Spiral Matrix
https://pintia.cn/problem-sets/994805342720868352/problems/994805363117768704
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 104. 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
代码:
#include <bits/stdc++.h> using namespace std; const int maxn = 1e5 + 10; int N; int num[maxn]; int ans[1010][1010]; int main() { scanf("%d", &N); for(int i = 0; i < N; i ++) scanf("%d", &num[i]); sort(num, num + N); for(int i = 0; i < N / 2; i ++) swap(num[i], num[N - i - 1]); int line, row; for(row = sqrt((double)N); row >= 1; row --) { if(N % row == 0) { line = N / row; break; } } int up = 0, down = line - 1, left = 0, right = row - 1, cnt = 0; while(true) { for(int j = left; j <= right; j ++) ans[up][j] = num[cnt ++]; if(++ up > down) break; for(int i = up; i <= down; i ++) ans[i][right] = num[cnt ++]; if(-- right < left) break; for(int j = right; j >= left; j --) ans[down][j] = num[cnt ++]; if(-- down < up) break; for(int i = down; i >= up; i --) ans[i][left] = num[cnt ++]; if(++ left > right) break; } for(int i = 0; i < line; i ++) { for(int j = 0; j < row; j ++) { printf("%d", ans[i][j]); printf("%s", j != row - 1 ? " " : "\n"); } } return 0; }
中午好!