代码:
java
class Solution {
public int maximalSquare(char[][] matrix) {
int m = matrix.length;
int n = matrix[0].length;
int[][]area = new int[m][n];
area[0][0] = matrix[0][0];
int max = 0;
for(int i=0;i<m;i++){
area[i][0] = matrix[i][0]=='1'? 1:0;
max = Math.max(area[i][0],max);
}
for(int j=0;j<n;j++){
area[0][j] = matrix[0][j]=='1'? 1:0;
max = Math.max(area[0][j],max);
}
for(int i=1;i<m;i++){
for(int j=1;j<n;j++){
if(matrix[i][j]=='0'){
area[i][j] = 0;
}else if(area[i-1][j-1]==area[i][j-1]&&area[i-1][j-1]==area[i-1][j]){
area[i][j] = area[i-1][j-1]+1;
max = Math.max(area[i][j],max);
}else{
area[i][j] = Math.min(Math.min(area[i-1][j-1],area[i-1][j]),area[i][j-1])+1;
}
}
}
return max*max;
}
}