Given a 01 matrix M, find the longest line of consecutive one in the matrix. The line could be horizontal, vertical, diagonal or anti-diagonal.
Example:
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| Input:
[[0,1,1,0],
[0,1,1,0],
[0,0,0,1]]
Output: 3
|
Hint: The number of elements in the given matrix will not exceed 10,000.
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| public class Solution {
public int longestLine(int[][] M) {
int result = 0;
if (M == null || M.length == 0 || M[0] == null || M[0].length == 0) return result;
for (int i = 0; i < M.length; i++) {
for (int j = 0; j < M[0].length; j++) {
int x = M[i][j];
if (x == 0) continue;
if (!(j > 0 && M[i][j - 1] == 1)) {
int k = j;
int count = 0;
while (k < M[0].length && M[i][k] == 1) {
count++;
k++;
}
result = Math.max(result, count);
}
if (!(i > 0 && M[i - 1][j] == 1)) {
int k = i;
int count = 0;
while (k < M.length && M[k][j] == 1) {
count++;
k++;
}
result = Math.max(result, count);
}
if (!(i > 0 && j > 0 && M[i - 1][j - 1] == 1)) {
int m = i;
int n = j;
int count = 0;
while (m < M.length && n < M[0].length && M[m][n] == 1) {
count++;
m++;
n++;
}
result = Math.max(result, count);
}
if (!(i > 0 && j < M[0].length-1 && M[i - 1][j + 1] == 1)) {
int m = i;
int n = j;
int count = 0;
while (m < M.length && n >= 0 && M[m][n] == 1) {
count++;
m++;
n--;
}
result = Math.max(result, count);
}
}
}
return result;
}
}
|