[LeetCode] Spiral Matrix II

最新推荐文章于 2022-09-17 14:49:30 发布

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本文介绍了一个C++实现的螺旋矩阵生成算法，该算法接收一个整数n作为输入，并生成一个n×n的矩阵，矩阵元素从1到n²按螺旋顺序填充。通过四个循环迭代填充矩阵的边界，实现了高效的螺旋顺序生成。

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

For example,
Given n = 3,

You should return the following matrix:

[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]
class Solution {
public:
    vector<vector<int> > generateMatrix(int n) {
        vector<vector<int> > res(n, vector<int>(n, 0));
        if(n == 0) return res;
        int x1 = 0,y1 = 0,x2 = n - 1,y2 = n - 1,k = 1;
        while(x1 <= x2 && y1 <= y2){
            for(int i = y1;i <= y2;i ++) res[x1][i] = k ++;
            for(int i = x1 + 1;i <= x2;i ++) res[i][y2] = k ++;
            if(x1 != x2)
                for(int i = y2 - 1;i >= y1;i --) res[x2][i] = k ++;
            if(y1 != y2)
                for(int i = x2 - 1;i > x1;i --) res[i][y1] = k ++;
            x1 ++;x2 --;y1 ++;y2 --;
        }
        return res; 
    }
};