Maximal Square || LeetCode

时间:2023-03-09 15:43:15
Maximal Square || LeetCode

dp.

#define MAX 1000
int rowLeft[MAX][MAX];
int colUp[MAX][MAX];
int dp[MAX][MAX];
void calRow(char **matrix,int matrixRowSize,int matrixColSize){
int i,j;
for(i=0;i<matrixRowSize;++i){
for(j=0;j<matrixColSize;++j)
{
if(matrix[i][j]=='1')
{
if(j==0)rowLeft[i][j]=1;
else rowLeft[i][j]=rowLeft[i][j-1]+1;
}
else rowLeft[i][j]=0;
}
}
}
void calCol(char **matrix,int matrixRowSize,int matrixColSize){
int i,j;
for(i=0;i<matrixRowSize;++i)
{
for(j=0;j<matrixColSize;++j)
{
if(matrix[i][j]=='1'){
if(i==0)colUp[i][j]=1;
else colUp[i][j]=colUp[i-1][j]+1;
}
else colUp[i][j]=0;
}
}
}
int min(int a,int b,int c){
int t;
t=(a<b?a:b);
t=(t<c?t:c);
return t;
}
int maximalSquare(char** matrix, int matrixRowSize, int matrixColSize) {
int i,j,maxSquare=0;
calRow(matrix,matrixRowSize,matrixColSize);
calCol(matrix,matrixRowSize,matrixColSize);
for(i=0;i<matrixRowSize;++i)
{ for(j=0;j<matrixColSize;++j)
{
if(i==0||j==0)
dp[i][j]=(matrix[i][j]=='1'?1:0);
else dp[i][j]=min(dp[i-1][j-1]+1,rowLeft[i][j],colUp[i][j]);
maxSquare=(maxSquare>dp[i][j]?maxSquare:dp[i][j]);
}
}
return maxSquare*maxSquare;
}

  

我这个空间复杂度有点高