1-4-之字形打印矩阵

/*
    题目描述：
        对于一个矩阵，请设计一个算法，将元素按“之”字形打印。具体见样例。
        给定一个整数矩阵mat，以及他的维数nxm，请返回一个数组，其中元素依次为打印的数字。
        测试样例：
            [[1,2,3],[4,5,6],[7,8,9],[10,11,12]],4,3
            返回：[1,2,3,6,5,4,7,8,9,12,11,10]
*/

#include <iostream>
#include <vector>
using namespace std;
/*
    实现斜之字打印矩阵：
    eg：矩阵A为：
        1  2  3
        4  5  6
        7  8  9
        10 11 12
    斜之字打印的结果为：
        [1,2,4,7,5,3,6,8,10,11,9,12]
*/
vector<int> printLine(vector<vector<int> > m, int t1, int t2, int d1, int d2, bool flag){
    vector<int> line;
    if (!flag){    // 从右上到左下打印
        while (t1 <= d1 && t2 >= d2){
            line.push_back(m[t1++][t2--]);
        }
    }
    else{    // 从左下到右上打印
        while (t1 <= d1 && t2 >= d2){
            line.push_back(m[d1--][d2++]);
        }
    }
    return line;
}

vector<int> printMatrix(vector<vector<int> > mat, int n, int m) {
    int t1 = 0;
    int t2 = 0;
    int d1 = 0;
    int d2 = 0;
    bool flag = true;
    vector<int> rt;
    while (t1 < n && t2 < m && d1 < n && d2 < m){
        vector<int> line = printLine(mat, t1, t2, d1, d2, flag);
        for (int i = 0; i < line.size(); i++)
            rt.push_back(line[i]);
        if (t2 == m-1)
            t1++;
        else
            t2++;
        if (d1 == n-1)
            d2++;
        else
            d1++;
        flag = !flag;
    }
    return rt;
}

/*
    NowCoder上面的题目较简单。
    矩阵A的打印结果为：
        [1,2,3,6,5,4,7,8,9,12,11,10]
*/
vector<int> printMatrix(vector<vector<int> > mat, int n, int m) {
    vector<int> rt;
    bool flag = true;
    for (int i = 0; i < n; i++){ // 逐行打印
        if (flag){    // 从左到右打印
            for (int j = 0; j < m; j++)
                rt.push_back(mat[i][j]);
        }
        else{    // 从右向左打印
            for (int j = m-1; j>= 0; j--)
                rt.push_back(mat[i][j]);
        }
        flag = !flag;
    }
    return rt;
}

test：
int main(){
    vector<vector<int> > matrix;
    vector<int> a;
    a.push_back(1);
    a.push_back(2);
    a.push_back(3);/*
    a.push_back(4);*/
    matrix.push_back(a);

    vector<int> b;
    b.push_back(4);
    b.push_back(5);
    b.push_back(6);/*
    b.push_back(8);*/
    matrix.push_back(b);

    vector<int> c;
    c.push_back(7);
    c.push_back(8);
    c.push_back(9);/*
    c.push_back(12);*/
    matrix.push_back(c);

    vector<int> d;
    d.push_back(10);
    d.push_back(11);
    d.push_back(12);/*
    c.push_back(12);*/
    matrix.push_back(d);

    vector<int> rt;
    rt = printMatrix(matrix,4,3);
    for (int i = 0; i < rt.size(); i++)
            cout << rt[i] << ",";
    return 0;
}