考点:
画图让抽象形象化
题目描述:
输入一个矩阵,按照从外向里以顺时针的顺序依次打印出每一个数字,例如,如果输入如下4 X 4矩阵: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 则依次打印出数字1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.
解题:
class Solution {
public:
vector<int> printMatrix(vector<vector<int> > matrix) {
vector<int> res;
int row = matrix.size();
int col = matrix[0].size();
if(row == 0 || col == 0){
return res;
}
int top = 0;
int right = col - 1;
int bottom = row - 1;
int left = 0;
while(top <= bottom && left <= right){
//left->right
for(int i = left;i <= right;i++){
res.push_back(matrix[top][i]);
}
top++;
//top->bottom
for(int i = top;i <= bottom;i++){
res.push_back(matrix[i][right]);
}
right--;
//最后剩下 只有一行或一列时,执行上面2个操作就已遍历完毕。
if(top > bottom || left > right)
return res;
//right->left
for(int i = right;i >= left;i--){
res.push_back(matrix[bottom][i]);
}
bottom--;
//bottom->top
for(int i = bottom;i >= top;i--){
res.push_back(matrix[i][left]);
}
left++;
}
return res;
}
};