对于一个矩阵，请设计一个算法从左上角(mat[0][0])开始，顺时针打印矩阵元素。
给定int矩阵mat,以及它的维数nxm，请返回一个数组，数组中的元素为矩阵元素的顺时针输出。
测试样例：
[[1,2],[3,4]],2,2
返回：[1,2,4,3]
[编程题]顺时针打印矩阵
importjava.util.*;
publicclassPrinter {
publicint[] clockwisePrint(int[][] mat,intn,intm) {
int[] a =newint[m*n];
if( mat ==null)
returna;
inti =0;
intj =0;
intk =0;
intstartX =0;
intstartY =0;
intendX = n -1;
intendY = m -1;
while( startX <= endX && startY <= endY ){
//如果只剩下一行
if( startX == endX ){
for( ; j <= endY ;j++,k++){
a[k] = mat[startX][j];
}
returna;
}
//如果只剩下一列
if( startY == endY ){
for( ; i <= endX ; i++,k++){
a[k] = mat[i][startY];
}
returna;
}
//将矩阵上边除右顶点添加到返回的数组中
for( ; j < endY ; j++,k++){
a[k] = mat[i][j];
}
//将矩阵右边除边下顶点添加到返回的数组中
for( ; i < endX ; i++,k++){
a[k] = mat[i][j];
}
//将矩阵下边除边左顶点添加到返回的数组中
for( ; j > startX ; j--,k++){
a[k] = mat[i][j];
}
//将矩阵左边除边上顶点添加到返回的数组中
for( ; i > startY ; i--,k++){
a[k] = mat[i][j];
}
i++;
j++;
startX++;
startY++;
endX--;
endY--;
}
returna;
}
}
编辑于 2016-03-11 22:18:27
回复(7)
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
vector<int>ans;
int order[4][2]={{0,1},{1,0},{0,-1},{-1,0}};//方向数组
int i=0,j=-1,start = 0;
while (true) {
int a = i+order[start][0],b=j+order[start][1];
if(!(0<=a&&a<n)||!(0<=b&&b<m)||mat[a][b]==INT_MAX)
start = (start+1)%4;
i=i+order[start][0],j=j+order[start][1];
ans.push_back(mat[i][j]);
mat[i][j] = INT_MAX;
if(ans.size()==n*m)
break;
}
return ans;
}
};
发表于 2016-04-11 11:34:21
回复(3)
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
// write code here
vector<int> ret;
int x1 = 0, y1 = 0; //左上角坐标
int x2 = n-1, y2 = m-1; //右下角坐标
while(x1 <= x2 && y1 <= y2){
for(int j = y1; j <= y2; ++j)
ret.push_back(mat[x1][j]);
for(int i = x1+1; i < x2; ++i)
ret.push_back(mat[i][y2]);
for(int j = y2; x1 < x2 && j >= y1; --j) //x1 < x2：只有在不是单一的横行时才执行这个循环
ret.push_back(mat[x2][j]);
for(int i = x2-1; y1 < y2 && i > x1; --i)//y1 < y2：只有在不是单一的竖列时才执行这个循环
ret.push_back(mat[i][y1]);
x1++; y1++;
x2--; y2--;
}
return ret;
}
};
发表于 2017-07-01 15:19:35
回复(0)
从左至右，从上至下，从右至左，从下至上循环打印就好
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m)
{
// write code here
vector<int> res;
int colbegin=0,colend=m-1,rowbegin=0,rowend=n-1;
int i=0,j=0;
while(colbegin<=colend && rowbegin<=rowend)
{
for(j=colbegin;j<=colend;j++)//right
res.push_back(mat[i][j]);
j--;rowbegin++;
if(res.size()>=n*m) return res;
for(i=rowbegin;i<=rowend;i++)//down
res.push_back(mat[i][j]);
i--;colend--;
if(res.size()>=n*m) return res;
for(j=colend;j>=colbegin;j--)//left
res.push_back(mat[i][j]);
j++;rowend--;
if(res.size()>=n*m) return res;
for(i=rowend;i>=rowbegin;i--)
res.push_back(mat[i][j]);
i++;colbegin++;
if(res.size()>=n*m) return res;
}
return res;
}
};
发表于 2017-05-20 11:07:23
回复(0)
为什么没人用Python?
class Printer:
# 返回循环次数
def iteration_num(self, n, m):
if(n <= m):
return n + (n - 1)
else:
return 2 * m
def clockwisePrint(self, mat, n, m):
l = []
for i in range(self.iteration_num(n,m)):
t = i / 4
if(i%4==0):
for j in range(0+t,m-t):
l.append(mat[0+t][j])
if(i%4==1):
for j in range(1+t,n-t):
l.append(mat[j][m-1-t])
if(i%4==2):
for j in range(m-2-t,-1+t,-1):
l.append(mat[n-1-t][j])
if(i%4==3):
for j in range(n-2-t,0+t,-1):
l.append(mat[j][0+t])
return l
编辑于 2016-05-02 05:32:11
回复(0)
classPrinter {public:vector<int> clockwisePrint(vector<vector<int> > mat, intn, intm) {// write code hereintstart=0;vector<int> imat;while(n>start*2&& m>start*2){intendX=m-1-start;intendY=n-1-start;//左-》右for(inti=start;i<=endX;++i)imat.push_back(mat[start][i]);//上-》下if(start<endY){for(inti=start+1;i<=endY;++i)imat.push_back(mat[i][endX]);}//右-》左if(start<endX&&start<endY){for(inti=endX-1;i>=start;--i)imat.push_back(mat[endY][i]);}//下-》上if(start<endX&&start<endY-1){for(inti=endY-1;i>=start+1;--i)imat.push_back(mat[i][start]);}++start;}returnimat;}};
发表于 2015-09-12 10:11:00
回复(2)
采用统一的格式,cnt代表循环的圈数。
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
// write code here
vector<int> res;
if(n==0 || m==0) return res;
int cnt=0,row=0,col=0;
while(res.size()<n*m)
{
while(col<m-cnt && res.size()<n*m)
res.push_back(mat[row][col++]);
col--,row++;
if(res.size()>=n*m) break;
while(row<n-cnt && res.size()<n*m)
res.push_back(mat[row++][col]);
row--,col--;
if(res.size()>=n*m) break;
while(col>=cnt && res.size()<n*m)
res.push_back(mat[row][col--]);
col++,row--;
if(res.size()>=n*m) break;
while(row>cnt && res.size()<n*m)
res.push_back(mat[row--][col]);
row++,col++;
if(res.size()>=n*m) break;
cnt++;
}
return res;
}
};
编辑于 2020-08-24 11:01:22
回复(0)
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
// write code here
int row = 0, col = 0;
int rrow = n - 1 , ccol = m - 1;
vector<int> arr;
while (1)
{
for (int i = col; i <= ccol; i++)
arr.push_back(mat[row][i]);
row++;
if (arr.size()==n*m)
break;
for (int i = row; i <= rrow; i++)
arr.push_back(mat[i][ccol]);
ccol--;
if (arr.size()==n*m)
break;
for (int i = ccol; i >= col; i--)
arr.push_back(mat[rrow][i]);
rrow--;
if (arr.size()==n*m)
break;
for (int i = rrow; i >= row; i--)
arr.push_back(mat[i][col]);
col++;
if (arr.size()==n*m)
break;
}
return arr;
}
};
发表于 2020-04-27 00:21:27
回复(0)
import java.util.*;
public class Printer {
public int[] clockwisePrint(int[][] mat, int n, int m) {
// write code here
int[] a=new int[n*m];
int index=0;
int topX=0, topY=0, lowX=n-1, lowY=m-1;
while(topX<=lowX && topY<=lowY){
if(topX==lowX){ //只剩下一行时
for(int i=topY; i<=lowY; i++)
a[index++]=mat[topX][i];
return a;
}
if(topY==lowY){ //只剩下一列时
for(int i=topX; i<=lowX; i++)
a[index++]=mat[i][topY];
return a;
}
for(int i=topY; i<lowY; i++)
a[index++]=mat[topX][i];
for(int i=topX; i<lowX; i++)
a[index++]=mat[i][lowY];
for(int i=lowY; i>topY; i--)
a[index++]=mat[lowX][i];
for(int i=lowX; i>topX; i--)
a[index++]=mat[i][topY];
topX++; topY++; lowX--; lowY--;
}
return a;
}
}
发表于 2018-06-28 21:35:07
回复(1)
public int[] clockwisePrint(int[][] mat, int n, int m) {
int tR = 0;
int tC = 0;
int dR = n - 1;
int dC = m - 1;
int index = 0;
int[] res = new int[n * m];
while (tR <= dR && tC <= dC) {
if (tR == dR) {// 只有一行的时候
for (int i = tC; i <= dC; i++) {
res[index++] = mat[tR][i];
}
} else if (tC == dC) {// 只有一列的时候
for (int i = tR; i <= dR; i++) {
res[index++] = mat[i][tC];
}
} else {
int curC = tC;
int curR = tR;
while (curC != dC) {// 从左到右打印
res[index++] = mat[tR][curC];
curC++;
}
while (curR != dR) {// 从上往下打印
res[index++] = mat[curR][dC];
curR++;
}
while (curC != tC) {// 从右往左打印
res[index++] = mat[dR][curC];
curC--;
}
while (curR != tR) {// 从下往上打印
res[index++] = mat[curR][tC];
curR--;
}
}
tR++;
tC++;
dR--;
dC--;
}
System.out.println(Arrays.toString(res));
return res;
}
发表于 2018-03-13 17:45:51
回复(1)
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
vector<int> r;
int left=0,right=m-1,top=0,bottom=n-1;
int i=0,j=0,k=0;
while(k<m*n)
{ for(i=top,j=left;j<=right;j++) r.push_back(mat[i][j]), k++; top++; if(k==m*n) break; for(j=right,i=top;i<=bottom;i++) r.push_back(mat[i][j]), k++; right--; if(k==m*n) break; for(i=bottom,j=right;j>=left;j--) r.push_back(mat[i][j]), k++; bottom--; if(k==m*n) break; for(j=left,i=bottom;i>=top;i--) r.push_back(mat[i][j]), k++; left++; if(k==m*n) break; } return r;
}
};
发表于 2017-12-04 18:51:03
回复(0)
import java.util.*;
public class Printer {
public int[] clockwisePrint(int[][] mat, int n, int m) {
int i=0;
int j=0;
int lmin=0;
int rmin=0;
int lmax=n-1;
int rmax=m-1;
int[] p = new int[n*m];
for(int count=0;count<n*m;count++){
p[count]=mat[i][j];
if(i==lmin&&j<rmax){
j++;
}
else if(i<lmax&&j==rmax){
i++;
}
else if(i==lmax&&j>rmin){
j--;
}
else if(i>lmin&&j==rmin){
i--;
}
if(i==lmin&&j==rmin){
lmin++;
rmin++;
lmax--;
rmax--;
i=lmin;
j=rmin;
}
}
return p;
}
}
public class Printer {
public int[] clockwisePrint(int[][] mat, int n, int m) {
int i=0;
int j=0;
int lmin=0;
int rmin=0;
int lmax=n-1;
int rmax=m-1;
int[] p = new int[n*m];
for(int count=0;count<n*m;count++){
p[count]=mat[i][j];
if(i==lmin&&j<rmax){
j++;
}
else if(i<lmax&&j==rmax){
i++;
}
else if(i==lmax&&j>rmin){
j--;
}
else if(i>lmin&&j==rmin){
i--;
}
if(i==lmin&&j==rmin){
lmin++;
rmin++;
lmax--;
rmax--;
i=lmin;
j=rmin;
}
}
return p;
}
}
发表于 2017-01-24 22:46:14
回复(0)
classPrinter {public:vector<int> clockwisePrint(vector<vector<int> > mat, intn, intm) {// write code herevector<int> matrix;inttR=0;inttC=0;intdR=n-1;intdC=m-1;while(tR<=dR && tC<=dC){intj;if(tR==dR){for(j=tC;j<=dC;j++){matrix.push_back(mat[tR][j]);}}elseif(tC==dC){for(j=tR;j<=dR;j++){matrix.push_back(mat[j][tC]);}}else{intcurC=tC;intcurR=tR;while(curC != dC){matrix.push_back(mat[tR][curC]);curC++;}while(curR != dR){matrix.push_back(mat[curR][dC]);curR++;}while(curC != tC){matrix.push_back(mat[dR][curC]);curC--;}while(curR != tR){matrix.push_back(mat[curR][tC]);curR--;}}tR++;tC++;dR--;dC--;}returnmatrix;}};
发表于 2017-01-12 16:15:10
回复(0)
class Printer {
public:
vector<int> clockwisePrint(vector<vector<int>>
mat, int n, int m)
{
// write code here
vector<int>result;
int left = 0;
int top = 0;
int right = m-1;
int bottom = n-1;
int x=0;
int y=0;
while(left<=right && top<=bottom)
{
for(x = left;x<=right;x++)
{
result.push_back(mat[top][x]);
}
top++;
if(top>bottom)
{
break;
}
for(y = top;y<=bottom;y++)
{
result.push_back(mat[y][right]);
}
right--;
if(right<left)
{
break;
}
for(x = right;x>=left;x--)
{
result.push_back(mat[bottom][x]);
}
bottom--;
if(bottom<top)
{
break;
}
for(y = bottom;y>=top;y--)
{
result.push_back(mat[y][left]);
}
left++;
if(left>right)
{
break;
}
}
return result;
}
};
发表于 2016-09-06 10:42:13
回复(0)
import java.util.*;
public class Printer {
public int[] clockwisePrint(int[][] mat, int n, int m) {
int startX = 0, endX = n - 1;
int startY = 0, endY = m - 1;
int[] res = new int[n * m];
int k = 0;
while (true) {
for (int i = startY; i <= endY; i++) {
res[k++] = mat[startX][i];
}
startX++;
if (startX > endX) {
break;
}
for (int i = startX; i <= endX; i++) {
res[k++] = mat[i][endY];
}
endY--;
if (startY > endY) {
break;
}
for (int i = endY; i >= startY; i--) {
res[k++] = mat[endX][i];
}
endX--;
if (startX > endX) {
break;
}
for (int i = endX; i >= startX; i--) {
res[k++] = mat[i][startY];
}
startY++;
if (startY > endY) {
break;
}
}
return res;
}
}
发表于 2016-08-28 09:42:57
回复(0)
class Printer {
public:
void print(vector<vector<int> > mat,vector<int> &vec, pair<int,int> point1,pair<int,int> point2){
for(int i=point1.second;i<=point2.second;i++)
vec.push_back(mat[point1.first][i]);
for(int i=point1.first+1;i<=point2.first;i++)
vec.push_back(mat[i][point2.second]);
for(int i=point2.second-1;i>=point1.second&&point1.first!=point2.first;i--)
vec.push_back(mat[point2.first][i]);
for(int i=point2.first-1;i>point1.first&&point1.second!=point2.second;i--)
vec.push_back(mat[i][point1.second]);
}
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
vector<int> vec;
int i=0;
while(2*i<=n-1&&2*i<=m-1){
print(mat,vec,pair<int,int>(i,i),pair<int,int>(n-1-i,m-1-i));
i++;
}
return vec;
}
};
发表于 2016-08-27 16:08:17
回复(0)
class Printer {
vector<int> vc;
public:
void printCircle(vector<vector<int> > mat,int x1, int y1,int x2,int y2) //定义一个打印一圈的函数
{
if (x1==x2&&y1==y2)
{
vc.push_back(mat[x1][y1]);
return;
}
else if (x1==x2&&y1!=y2)
{
for (int y = y1; y <= y2;y++)
{
vc.push_back(mat[x1][y]);
}
return; //跳出函数，不然可能继续执行下面的函数，重读数据。
}
else if (y1==y2&&x1!=x2)
{
for (int x = x1; x <= x2;x++)
{
vc.push_back(mat[x][y1]);
}
return;
}
for (int y = y1; y < y2;y++)
{
vc.push_back(mat[x1][y]);
}
for (int x = x1; x < x2;x++)
{
vc.push_back(mat[x][y2]);
}
for (int y= y2; y>y1;y--)
{
vc.push_back(mat[x2][y]);
}
for (int x = x2; x > x1;x--)
{
vc.push_back(mat[x][y1]);
}
}
vector<int> clockwisePrint(vector<vector<int> > mat, int n, int m) {
// write code here
int startX = 0, startY = 0;
int endX = n - 1, endY = m - 1;
while (startX <= endX&&startY <= endY)
{
printCircle(mat, startX, startY, endX, endY);
startX++;
startY++;
endX--;
endY--;
}
return vc;
}
}
编辑于 2016-06-27 18:21:50
回复(0)
import java.util.*;
public class Printer {
int t = 0;
public int[] clockwisePrint(int[][] mat, int n, int m) {
// write code here
int a[] = new int[m*n];
int start = 0;
while(n>start*2&&m>start*2)
{
print(mat,n,m,start,a);
start++;
}
return a;
}
public void print(int[][] mat, int n, int m,int start,int a[]){
int endx = n-1-start;//
int endy = m-1-start;
for(int i = start;i<=endy;i++)
{
a[t++] = mat[start][i];
}
if(start<endx)
{
for(int i = start+1;i <=endx;i++ )
a[t++] = mat[i][endy];
}
if(start<endy&&start<endx)
{
for(int i= endy-1;i>=start;i--)
a[t++] = mat[endx][i];
}
if(start<endx-1&&start<endy)
{
for(int i = endx-1;i>=start+1;i--)
a[t++] = mat[i][start];
}
}
}
发表于 2016-04-26 21:42:56
回复(0)
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