矩阵中的路径

题目描述

请设计一个函数，用来判断在一个矩阵中是否存在一条包含某字符串所有字符的路径。路径可以从矩阵中的任意一个格子开始，每一步可以在矩阵中向左，向右，向上，向下移动一个格子。如果一条路径经过了矩阵中的某一个格子，则该路径不能再进入该格子。 例如 a b c e s f c s a d e e 矩阵中包含一条字符串"bccced"的路径，但是矩阵中不包含"abcb"路径，因为字符串的第一个字符b占据了矩阵中的第一行第二个格子之后，路径不能再次进入该格子。

#include <iostream>

using namespace std;

bool hasPathCore(char* matrix, int rows, int cols, int row, int col, int pathLength, char* str,bool* visited)
{ 
bool hasPath = false;

if(str[pathLength] == '\0')
{
return true;
}

if (row >= 0 && row < rows && col >=0 && col < cols && !visited[row * cols + col] && str[pathLength] == matrix[row * cols +col])
{
++pathLength;
visited[row * cols + col] = true;
hasPath = hasPathCore( matrix, rows, cols, row-1, col, pathLength, str, visited)
||hasPathCore( matrix, rows, cols, row, col-1, pathLength, str, visited)
||hasPathCore( matrix, rows, cols, row+1, col, pathLength, str, visited)
||hasPathCore( matrix, rows, cols, row, col+1, pathLength, str, visited);

if (!hasPath)
{
--pathLength;
visited[row * cols + col] = false;
}
}
return hasPath;
}

bool hasPath(char* matrix, int rows, int cols, char* str)
{
int i,row,col;
if(matrix == NULL && rows < 1 && cols < 1 && str == NULL)
return false;

bool* visited = new bool[rows * cols];
//将visited指向的某块内存空间的前rows*cols字节的内容全部设置为0的ASCII值
//memset(visited, 0, rows * cols);

for (i = 0; i < rows * cols; i++)
{
visited[i] = false;
}

int pathLength = 0;

for(row = 0; row < rows; row++)
{
for (col = 0; col < cols; col++)
{
if(hasPathCore(matrix, rows, cols, row, col, pathLength, str, visited))
{
return true;
}
}
}

delete[] visited;

return false;
}

void Test(char* testName, char* matrix, int rows, int cols, char* str, bool expected)
{
    if(testName != NULL)
        printf("%s begins: ", testName);

    if(hasPath(matrix, rows, cols, str) == expected)
        printf("Passed.\n");
    else
        printf("FAILED.\n");
}

//ABCE
//SFCS
//ADEE

//ABCCED
void Test1()
{
    char matrix[] = "ABCESFCSADEE";
    char* str = "ABCCED";

    Test("Test1", (char*)matrix, 3, 4, str, true);
}

//ABCE
//SFCS
//ADEE

//SEE
void Test2()
{
    char matrix[] = "ABCESFCSADEE";
    char* str = "SEE";

    Test("Test2", (char*)matrix, 3, 4, str, true);
}

//ABCE
//SFCS
//ADEE

//ABCB
void Test3()
{
    char matrix[] = "ABCESFCSADEE";
    char* str = "ABCB";

    Test("Test3", (char*)matrix, 3, 4, str, false);
}

//ABCEHJIG
//SFCSLOPQ
//ADEEMNOE
//ADIDEJFM
//VCEIFGGS

//SLHECCEIDEJFGGFIE
void Test4()
{
    char matrix[] = "ABCEHJIGSFCSLOPQADEEMNOEADIDEJFMVCEIFGGS";
    char* str = "SLHECCEIDEJFGGFIE";

    Test("Test4", (char*)matrix, 5, 8, str, true);
}

//ABCEHJIG
//SFCSLOPQ
//ADEEMNOE
//ADIDEJFM
//VCEIFGGS

//SGGFIECVAASABCEHJIGQEM
void Test5()
{
    char matrix[] = "ABCEHJIGSFCSLOPQADEEMNOEADIDEJFMVCEIFGGS";
    char* str = "SGGFIECVAASABCEHJIGQEM";

    Test("Test5", (char*)matrix, 5, 8, str, true);
}

//ABCEHJIG
//SFCSLOPQ
//ADEEMNOE
//ADIDEJFM
//VCEIFGGS

//SGGFIECVAASABCEEJIGOEM
void Test6()
{
    char matrix[] = "ABCEHJIGSFCSLOPQADEEMNOEADIDEJFMVCEIFGGS";
    char* str = "SGGFIECVAASABCEEJIGOEM";

    Test("Test6", (char*)matrix, 5, 8, str, false);
}

//ABCEHJIG
//SFCSLOPQ
//ADEEMNOE
//ADIDEJFM
//VCEIFGGS

//SGGFIECVAASABCEHJIGQEMS
void Test7()
{
    char matrix[] = "ABCEHJIGSFCSLOPQADEEMNOEADIDEJFMVCEIFGGS";
    char* str = "SGGFIECVAASABCEHJIGQEMS";

    Test("Test7", (char*)matrix, 5, 8, str, false);
}

//AAAA
//AAAA
//AAAA

//AAAAAAAAAAAA
void Test8()
{
    char matrix[] = "AAAAAAAAAAAA";
    char* str = "AAAAAAAAAAAA";

    Test("Test8", (char*)matrix, 3, 4, str, true);
}

//AAAA
//AAAA
//AAAA

//AAAAAAAAAAAAA
void Test9()
{
    char matrix[] = "AAAAAAAAAAAA";
    char* str = "AAAAAAAAAAAAA";

    Test("Test9", (char*)matrix, 3, 4, str, false);
}

//A

//A
void Test10()
{
    char matrix[] = "A";
    char* str = "A";

    Test("Test10", (char*)matrix, 1, 1, str, true);
}

//A

//B
void Test11()
{
    char matrix[] = "A";
    char* str = "B";

    Test("Test11", (char*)matrix, 1, 1, str, false);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();
    Test7();
    Test8();
    Test9();
    Test10();
    Test11();

return 0;
}